Sunday, 18 June 2017

Dungeon Master: Players Shining

Keeping all of your players involved and relevant is one of the things a Dungeon Master wrestles with. However, it's also something that is difficult to deal with. Magic items can do a lot to shift player focus. This is especially true in combat. However, a clever player can also make this happen in other areas of the game. There is also the question of whether it is fine to have some players that are focused more than others. What if you have a shy player? These are the ideas and aspects I hope to work through by putting into words.

What Can Shift Focus

I've already mentioned in passing that magic items can shift the focus to one player or character. However, it goes further than that. The location that something takes place in can also shift the focus. If you have a character that is native to the area, they will naturally be a focus for events in the story. The type of adventure can also do a lot to make some characters more of a focus than others. In D&D 5th edition they have what they call the 3 pillars of the game (combat, exploration, and role-play/interactions). Some classes are better and one than another in certain situations. You might find that the situation or campaign you came up with will naturally gravitate towards certain players or their characters. There is also the question of player experience or mastery of the rules. Some players can just work their skills and weaknesses in amazing and clever ways that makes them shine.

Should All Players Shine Equally?

When you first think about how players shine during the course of a game, the first thought that usually comes to mind is that they should all be equal. This isn't necessarily true. Or more precisely, what exactly does that mean? What I find is more accurate is that there is a certain amount that if you don't meet, your player(s) will feel unfulfilled. For some, this amount is more than others. They'll also get to shine in different moments and not all moments are perceived equally. It might also depend on the long view of things as well. They might want things to balance out in the long run, but for this session they might be fine taking a back seat. After all, last week's session was theirs.

Round Robin Focus

You could try to make a few of your party members the centre of focus for the session. The focus characters will be rotated between sessions and the end result is that everyone roughly gets the same amount of focus. It's kind of like when a TV show has episodes focusing on different characters. Of course, not everyone likes that kind of thing. It's also a bit different. You have the risk that someone might accidentally hijack the session by doing something clever or thinking outside the box. That might very well make sense, but it defeats the purpose of this approach.

Design Situations

You could instead design the situations players will end up in. Players will then decide how to approach the problem and when they do, decide who will shine in that moment. It feels quite naturally and lets the players decide who shines partially, but it still keeps the possibility of someone being overshadowed.

You could also combine the two ideas above, which is what more often happens naturally. You design situations for your players but you might try to target some of the strength of your players. There will be a combat encounter for your combat focused character, some kind of social interaction, maybe a history related element, and end it with a twist that involves one of your player characters.

Shy Players

Shy players are one of the harder ones to bring into the game. From my experience, they tend not to need as much time shining to feel like they contributed enough to the session. It can also be shining in a different way. You also don't really want to try and force them into the centre of attention, especially at the start. What I find typically works best is to let them get comfortable and choose when to be the centre of attention. At first, this might not seem to work. However, once they get used to the game and the people they are playing with I've usually seen them have no issue jumping in. I chose to say tend here because it really does depend on the person in question.

The early part can be a bit rough though. In this case, you probably don't want to have someone else stepping on their toes all the time. Having one rogue played by a shy person and another played by a social butterfly is often a recipe to have the shy person overshadowed (it isn't always the case, particularly if the two builds are very different with very different skill sets). Some overlap isn't so bad, since someone else can pick up some of the slack just in case. However, there needs to be some individuality and some cases where the shy character makes the most sense. It can also be a problem when the shy person feels more comfortable and finds themselves competing with someone else in the area that overlaps.

Accidentally Overshadowing

There are some things, magic items in particular, that could cause a player to be accidentally overshadowed. Easy access to healing magic items in particular can make things harder for the cleric. Likewise, certain magic items can make combat far easier for the player that has them. I usually weight magic items that don't have a limited number of uses very carefully to prevent this. Such items are fine, however, if your party is lacking something. If your 2 player party doesn't have a cleric but they have easy access to healing magic, there isn't a problem. Otherwise, care should be taken. It can especially be an issue at low levels. At that time even small bonuses make large differences and access to abilities that target large areas are disproportionately powerful. It's also a good idea to consider whether a magic item will make a particular class feature or character feature redundant. A sentient, and autonomous pair of lock picks can be a rogue's worst nightmare.

Sunday, 11 June 2017

Dungeon Master: Where to Start

You did it! You decided to be a Dungeon Master! We are happy to have you join our ranks. However, now you need a campaign. Starting to plan one out can be difficult, especially if you've never done it before. So, let's talk about how to start planning one and what approaches are available. Starting can be one of the hardest parts so hopefully I'll be even a little bit of help. Feel free to ask questions as well.

Relax, You'll Be Fine

First thing first. If you are running a game for the first time, relax. It's not so scary. There is some responsibility and some preparation work that goes into it but it'll be fine. We all had to start at some time before getting where we are. Being a Dungeon Master is a very fun and in a different way than being a player.

Do You Know Your Players?

If you are starting off as a new Dungeon Master with a group you've played with for a while, you'll know quite a bit about your players and what kind of game they like to play. However, you might want to ask them some questions ahead of time if you plan to try something very different than they are used to. If you don't know your players at all, it might be worth having a session to just talk about what they want and taking care of the ground work. I find that with some of the people I play with, this can be a tall order. Getting everyone together in a physical place to take care of that can be tricky and might not seem worth the effort for your players, though they'd be willing to do it for an actual game. For this reason, this kind of stuff quite often ends up in a pre-game Skype call from what I've seen.

If you are playing with a brand new group, you should be asking questions a head of time. You should also be ready to go in a different direction if it turns out that what you had planned isn't being received as well as you thought it would. You can do that, and you should be prepared to. Even if it is being well received, it could go in a direction you didn't expect. This is also true for groups you know, but I find that new players are more surprising for me until I get a feel for them. That's not to say the ones I'm used to get boring and I can perfectly predict them, but I get more of a feel for them. However, the first few sessions of a campaign can be more fluid as you get things rolling.

Pre-Made

There is a large amount of pre-made material available for use in tabletop role-playing games. Some will obviously have more material than others. However, one strategy to start a campaign is to go into the pre-made adventures or campaigns. It's a different set of skills than coming up with a campaign from scratch, but it provides a starting point. That starting point should in theory come from someone with more experience than you and so help you make your first campaign better. Even if you don't run it exactly as written (this is very common), it can work as a good starting point and result in encounters, characters, situations, and story that you wouldn't otherwise think of. I will say though that you should make sure to know what you want to do though. You aren't just running the adventure as written; you'll be bringing it to life and making it your own. This means you need to have a good feeling for it, even if you are changing things.There will also always be blanks in the adventure that you'll need to fill in. I find it's best to see it as a reference and inspiration instead of a script that needs to be followed.

From Scratch

World First

You can start your own campaign by thinking about the sandbox it'll take place in. Building up the world to have its own interesting elements can help you come up with your own, hopefully unique, conflict. Different worlds help inspire, or at the very least reinforce, different kinds of stories because of their rules. It can also allow an interesting place for your players to go feeling around for what they want to go after. You can dangle multiple setups in front of them and just go after the one that gets a bite. This becomes a lot more enjoyable if the place that they are going through is interesting. You don't need to come up with the entire world at one time, but you should at least think about the place where things will start.

Conflict First

Flipping things, you can think of the rough outline of your big bad(s). Characters are an important part of stories and villains are often the best remembered ones of them all. Making their motivations, their means, and their power make sense goes a long way. It can also help you come up with completely different stories when you come up with a particular villain you've never thought of before. Villains and conflict can also be very inspirational. A certain kind of character, such as a classic vampire, might inspire a Gothic style location (oh, hello Raveloft). It could also inspire a different location by taking that classic style of villain and putting them in an unfamiliar situation. Your conflict could be not centred around one being either and instead be around a force of nature, a war featuring many different complex threads but a small number of goals at their centre, or something far more bizarre (as gods, hunting down piece of an item that was never meant to enter the mortal realm over centuries).

Tools

You can arrive at the same stories regardless of which of the above you choose. It's just a technique to help get you thinking and it's sometimes useful to change to the other to get the creative juices flowing and coming up with new campaign ideas. If you are having trouble coming up with an idea in the first place, trying one approach and then the other can help you get some ideas you can turn into a workable campaign after a couple more passes through the above.

Too Many Ideas

That's great! Write them down. You never know when it might come in handy. You might use one later for a subplot, or an alternate climax, a new villain, the next story, etc. There are a lot of uses for such a thing. Now, we need to pick one. Sometimes, it helps to just leave it for a bit and look at them afterwards. Sometimes you'll find yourself drawn to a couple while you are doing things and realize that you really want to run one of those. If it's just one, that's great! We got our idea. Otherwise, you might just need to sit down, look at what your players want, look at what you have, reduce to a smaller list and finally make a tough choice. This stuff will be quite high level so it's very unlikely you'll be dooming yourself here. However, the right idea can make things very easy going forward because it makes role-playing and improvisation for you a breeze.

Sanity Check

When I have something that you want to run, I typically like to run it through a sanity check. This takes the form of looking at the situations and campaign as a player would and think about what options I would have. What I'm trying to do here isn't predict what my players will do, but make sure that the situations I have allow for multiple solutions. A situation on its own might be fine, but the next scenario might presume something about the previous. If I find something like this, I'll either change it so it doesn't or note that there will be a factor that influences the situation from before. Depending on how the rest of the campaign goes before that point, this factor may be different because of how my players dealt with it. If it's so important that I can't leave it as just a note, it's probably too railroady and I'll change it. 

Other Useful Things I've Written

There are some other things you can read as well. Out of the things I've written I would recommend precedent, reducing difficulty through situation, degrees of influence, and designing a combat encounter. These are additional readings and you can be perfectly fine without them. You just might find them a bit helpful. You can always come back later if one of those elements sounds interesting. When starting out it's not good to get overwhelmed.

Sunday, 4 June 2017

So You've Ended Your Campaign

All campaigns eventually come to an end. Hopefully it was because of the natural end being reached instead of being left unfinished. Regardless, we have to make decisions about what we will do next and these decisions can be extremely important for the success of the new campaign. It's also not a very simple subject. As usual, I hope my thoughts on the matter will be of some help.

Rolling Into the Next One

One of the big things that need to be decide is whether a new campaign will be started right away or a break will be taken. When I say right away, I don't mean necessarily that things will continue on the old schedule. The beginning of a campaign has a way of often being more complex than a normal session because many details about the world, characters, player characters and the general story going forward needs to be thought up. However, you can still have the first session of your new campaign scheduled in 2 or 3 weeks. I typically like to do it this way because I find it is much easier to keep things rolling if the people involved know when the next session is. Trying to gather people back together after a break of unknown length can be its own challenge. In some cases, this is very hard to avoid. If it will be a month or so away it can be very difficult for people to predict if they will be free. However, if they already liked playing in your games and want more game time they will typically give it their best shot.

Switching the Dungeon Master

Rotating the roles can be a great way to mix things up. There are some people who like to play and some who like to run the game. If that's how the group runs and they are happy, that's great. However, I've also seen groups where people enjoy being on both sides of a game. It can also be helpful for a Dungeon Master to get some time to let their ideas stew. Being able to have a campaign going and still working on their next campaign can be an amazing blessing for a Dungeon Master. One thing that I will warn about, however, is some unintentional leaching. You might think of things that would make a great addition to the campaign you are playing in but would be out of place in your own. You also want to be wary of having your next campaign being too similar to the current one as well.

New Campaign Length

One of the decisions that tend to be made is about the length of a new campaign. Many people want to just keep the game going until interest is lost or they run out of things to do. Some, however, prefer to have an ending in mind and work towards it. A short campaign may just span levels 1-5. The nice thing about shorter campaigns is that they can be extended and built on if needed. It also means that a suitable and manageable big bad can be chosen for the planned range. The risk is that things may seem a bit disjointed if no thought towards the next possible extension is made before the end. I find many people make these kinds of decisions even if they don't realize it. These choices can be seen from elements such as world building, enemy choices, magic items presented and sometimes even player advice (when it comes to character building, some builds work better than others at certain level ranges).

Switching Groups

The end of a campaign can be a good time to switch groups if things weren't going well. I also find that it's easier to handle when a player leaves at the end of a campaign compared to leaving in the middle of one. That way, it gives time to find other players if needed instead of scrambling in the middle. There is also the barrier of getting the new players caught up and integrated so they don't feel left out, which is avoided when a new campaign is being made.

Taking A Break

Personally, I view this option as a last resort. I find it much harder to find the time later instead of when I already have time scheduled. It can also be a bit hard to jump back in due to some of the reasons I mentioned earlier. Campaigns can run longer or shorter than expected but they typically run a few months at least from my experience. However, if in a slump it can be a great way to get rid of fatigue and get excited about the game again. I've seen some people for who this works great. Personally though, I prefer playing anyway and the fatigue goes away on its own when new, exciting situations are encountered.

Sunday, 28 May 2017

Dungeon Master: Recycling Story Ideas

Inspiration can come from many places. It's great when it just hits and results in something new and unique. However, that kind of moment tends to be rare. Instead, I often find myself needing to take inspiration from something already existing and trying to turn that into something that feels fresh and new. That is easier said than done. I'll share some of what I find sometimes helps me. Hopefully at least one of you out there finds it useful or at least interesting. In this case I'm talking about home games that you don't plan to have published. Some things, like improperly lifting things, can get you into hot water if you try to publish it. The distinction between these different types can sometimes be muddy but that's fine. They are meant as a starting point and to help inspire you.

Distilling

Distilling is one of the easier methods and also a common favourite. What you do is start with something you like or at the very least find interesting for one reason or another. Then, you start to hack away and remove details or elements to get it into a form that contains what you see as the essence of what you started with. Since this is naturally based on the interpretation of the person who is doing the process, it can be very personal and even create different results if you try it after some time has passed. Many complex works also have more than one thread or idea that runs through them. This brings even more variation to the technique. Once you get this essence, you can then build back up to something new. When you are done, it should look different than what you started with.

Let's try an example. Star Wars has a long history and also quite a few well liked characters. Let's try to hack off some of the characters first. We'll remove Lea and Han Solo, leaving us with Luke and Darth Vader. We can decide that the central idea between those two was something along the lines of temptation, with Luke tempting Vader to the light (successfully, at the end) and Vader trying to tempt Luke to the dark side. Now we can start trying to build it up. Maybe we can have a character who leads armies, as the second in command, against a rival faction. He wants his son to take his side and succeed him but his son feels conflicted about what he would have to do since he is disillusioned with his own faction. At this point, we can have the son change sides and throw our characters into things. Or, we can decide that it might happen and let your players influence things to see where it might go (decide based on their actions or have some modifier bonus based on their actions to a roll). If we keep filling out the specifics, we can end up somewhere different than where we started pretty quickly. What if it was from his first taste of combat? What if it was because of a particularly sneaky move that was done (poisoning water, assassinating a child king, etc.)? Was this event a normal occurrence or a common exception? Maybe they don't want to switch sides but want no part of things until someone with a very good diplomacy bonus comes along? The key is not to keep too much of the original and not to think of where we started from when building back up. We want something distinctly different when we build the scenario back up.

Lifting

Sometimes, we can just shamelessly borrow ideas or scenarios from something. When talking about something reasonably complex, you can often borrow one or two things pretty easily without it being too obvious or too blatant. It still needs to be small enough that it can be fit into the scenario seamlessly. If you steal the entire story of Star Wars, someone will notice. If you steal just the Han Solo arc of coming back at the end to help unexpectedly for something other than money, you might get away with it. Maybe just once though.

Coat of Paint

There are a lot of things out there to read, watch, and play. Enough that you can't go through all of it in one lifetime. This means that if you know of something obscure enough, you can take significant chunks of it, cover it with some fresh paint, and use it. Old space opera stuff tends to work quite well, though you'll need to be a bit careful to avoid comparisons to Star Wars when that wasn't your intention. Obscure historical events also work quite well for this sort of thing. No matter where you are, there tends to be at least one place in the world or one period of time where your players have no idea what happened. The Russian Time of Troubles is one of my favourite situations since it makes for very interesting and easy conversions. It's really a great source of inspiration for a particular kind of campaign and story.

It has to be obscure though. If you use this kind of technique, you are taking a large part from the original. You can of course distill a historical event, but that would be distilling and not adding a coat of paint, really.

Crashing

Instead of removing things to get down to the essence, you can add things. One thing I've seen used successfully, though not as commonly as the above, is to take two or more different ideas, story lines, or even collections of tropes and throw them all in. Though the elements on their own aren't very unique, the way they fight each other can end up being so. It typically works well for more comedic games from what I've seen. It can work for more serious games as well, as so many works have multiple plot lines and elements, but it is generally harder to pull off. 

Your Own Campaigns

Everything I've mentioned above can be attempt on your own campaign games or even published adventures. However, I'd be careful with doing this on a group that has seen the original. You run the risk that it will be too similar to the original. You can probably get away with distilling, but the others may come off too blatant and similar. It can also defeat the original purpose of coming up with new ideas for your tabletop game. 

Sunday, 21 May 2017

Dungeon Master: Ending Campaigns

Beginnings are hard, but so are endings. As a Dungeon Master, you want the campaign to end well, your players to be happy and for campaign stories to be told for years to come. However, they can be extremely tricky. Will you ever come back to those characters again? What do the players want their characters to do after? Do they want a slow ending with a wind-down and time to look back on their campaign fondly, or end on the high of an epic situation? With that in mind, I hope to share some of my experience and hope it helps someone out there.

Slow or Quick Burn Ending?

An important choice to make is between a slow or quick burn ending. A slow burn allows reflection, to think about where things started from and where they are now, and maybe tie up some loose threads. Some people really like this kind of thing. If you do, it really helps to show the direct results of player's actions. Maybe show a city that was destroyed at the start of your campaign now rebuilt, though not yet achieving the same grandeur. It can also be a time to show the results of some less than good actions and the lasting consequences. Not everything that happens immediately after will be because of the players, but having a good portion of it helps. I also find that it tends to be what players want in their ending. If you go too far away from that, it starts feeling more like setup for another campaign instead of closure for this one. You also don't want to turn it into a lecture and instead keep your players acting through the ending. Even for people who like a slower ending, there is such a thing as too slow and too long. You want to address the important details but not to waste time.

There is also the far rougher approach of ending things almost right after the climax. Leave the details of recovery and what the player characters do up to the imaginations of the players. Instead, you might do some minor thread tying but very little. If the climax happened this session, the rest of the campaign is finished this session as well. The good thing about this is that it wraps things up on a high. This, of course, also depends on how well received the climax of the campaign was. If the response was lukewarm or worse, it might be a good idea to go for a slower burn, particularly if your players have no strong opinion one way or the other. I say might because it could also just make things worse. The idea is to not do too much more than you have to when ending quickly. Let the story told until now speak for itself. Being in the dark can be a good thing.

Beware Unmet Player Ideas

Chances are that your players have ideas of where they want things to go after they stop playing. Neatly summarizing that kind of stuff without their involvement often ends badly because it's about their characters. They don't want you to tell them about what their characters did. They want to tell you what they would try to do and you to put obstacles in their way. However, I find that this kind of collaborative storytelling is harder at the end of a campaign because of the scale involved. A campaign's path is composed of many checks, events and decisions. Trying to work with this at a higher level has a way of summarizing details. However, your players care about details, particularly where their characters are concerned. They know them better than anyone. Something that might sound fine to you might go completely against what their character would do in their hands. It might also seem insignificant in scale, but to a player that spent months or years in their character's head, it can be jarring to say the least. Campaign epilogues are not an easy thing on the Dungeon Master side.

The Next One

Will the same characters ever come back? It can be quite awkward to backtrack on previous epilogue explanations of what happens next because you didn't expect that there would be another campaign. It can also be an unintentional shot in the foot to your next campaign if you have to start plotting around your epilogue, particularly if you didn't give it too much thought ahead of time. If you feel that there might be more or aren't sure, it might be a good idea to just wrap things up quicker and not to focus too deeply into specifics that occur after. That way, players can imagine where things go from there if there is never another session, and the Dungeon Master has a far easier time if the characters ever return. Of course, the players will go after what they wanted for their ideal ending but in this way collaborative storytelling is maintained instead of the Dungeon Master deciding the ending. You may also decide to make your next campaign take place in the same world and those old player characters may make appearances (this is also a matter of taste as some players love it and some completely hate it). Best to ask permission first to avoid difficulties if you decide to do so. You can, and in fact I prefer to when using player characters, ask your player about what their player would have done and said in that situation.

Sunday, 14 May 2017

Dungeon Master: Weird Narratives

Sometimes, we Dungeon Masters like to shake things up a little bit. You know, do something we haven't done before. Unleash some chaos. Subvert rules and expectations we usually adhere to. These kinds of desires can lead to very entertaining and fresh sessions. However, there are also some difficulties with this approach. I hope to address some of them and hopefully make things a little easier for someone out there in the process.

What's a Weird Narrative?

For my purposes and for this article (blog post, whatever you want to call it), what I mean is a type of narrative that does not follow the typical rules (could be mechanical or could be thematic, such as good always wins), methods, ideas, or take place in a typical setting (a setting is influenced by the previous things I mentioned but might not be thought of the same way) that the players are used to. Based on that definition, the real meaning could vary largely from group to group. Since expectations also change over time, the same kind of narrative could be "weird" if enough time has passed. If you haven't seen it for a 5 years, it could be weird to you and a pleasant surprise.

The Start

When your players are first thrown into a weird narrative, a couple of things can happen. New players tend to be cautious from my experience because they don't know what to expect. They often don't even have a firm grasp on the rules so are often willing to go along with whatever comes. However, more experienced players have an idea in their heads of what the session will be like. This can be a factor when you have experienced players join your in-progress campaign, but it can be far worse when the basic assumptions they have are invalid and they don't know it.

It might be a good idea to warn your players coming into it that things will be different. You can also do this in less direct ways through the game itself. Having an assumption shown to be false right away makes it just as obvious but sometimes doing it in-game can really enhance the experience. On the narrative side though, your players might end up freezing if they don't know what to do. If you have some players that will just make a decision and roll with it, it's not a problem. Otherwise, the players will need at least a little bit of knowledge. I'd also argue that giving your players some knowledge tends to work better. This is because often times the characters your players will be playing will be familiar with the weirdness even though your players won't be (unless your players got pulled into the world D&D cartoon style).

Grasping the Rules

When you play around with non-standard narratives, either through rules/world reasons or through story telling itself, your players end up being in the dark on a large variety of subjects. This is good. Some fumbling around in the dark can make for a fun experience. However, I'd say you can't keep that state going on forever. To do so would be to try to violate cause and effect. As your players take actions and see their results, they will get a sense of how things work and start to figure things out. This won't give them 100% clarity, but it does make it no longer completely unknown.

Discovery

I find that a large part of the fun in these kinds of cases is the discovery. How do things work? What is the relationship between those 2 characters? Why are things as they are? What makes the narrative weird is that they probably don't know what to expect. It's not just a subversion, where they expect one thing and get another. It's different from normal so they don't quite know what to expect. However, the discovery has to come. The goal is not to try and hold of the players understanding of the rules or to keep the players away from the discovery. It's to make it impactful and earned when it does come. It also doesn't have to be, and usually isn't, a single discovery. A weird narrative tends to have many different twists and turns.

Don't Hold Things Back for the Sake of Holding Them Back and Don't Let It Become Pure Randomness

Always a Dash

Most campaigns I've played in have at least one part where the players can't be sure about which option leads to the best outcome. This is a good thing. Being completely predictable isn't a good thing. Likewise, being completely unpredictable isn't a good thing either since it leads to a feeling that choices don't matter. It's still not to enough of an extent to make it a weird narrative, since weird narratives rely on the weirdness and on the players being in the dark (it's almost a mild confusion). However, it is a somewhat similar idea. It's based on what the players are used to and novelty is part of the reason for them.

An Example

The story of Planescape: Torment takes place in a rather odd setting (most Planescape fans would agree) and features a story I'd argue is quite different from the norm. However, it is governed by rules and as you go through the story, you discover things. The rules aren't continuously broken. There is a consistent narrative. Of course, if you've been playing in that setting for a while, it will no longer feel weird to you.

Sunday, 7 May 2017

Dungeon Master: Ambushes

There are many tactical situations players can find themselves in. An iconic classic is the ambush. It mixes things up and provides the opportunity to safely remove a threat, to have a chance to win in a situation where otherwise there'd be no hope, or to put real fear into your players. However, it's a careful balancing act that is easy to mess up. A challenging ambush against your players could end up as an embarrassing defeat for the players. Having been on every end of an ambush I can think of, I hope my insights will provide some use to someone out there.

A Player Ambush

A Weak Enemy

An ambush against a weak enemy, either due to numbers or the monsters themselves, only makes things even easier. This typically results in an even less climactic game and in many cases makes players wonder why they even bothered. The more cinematic your campaign is, the more that this is probably true. However, there are exceptions. The most common one is if your players like dungeon delving. A weak and easy encounter can still provide tension in this case because your players are expecting a long war of attrition. The tension then doesn't come from the encounter itself but from the possibility of being starved of valuable resources that they'll need later. I've also seen it used for great effect for the story. Wait, this is the big bad's elite force? Something seems wrong. And then the trap is sprung or the complication is found. It can also be used to say something about the enemy and for the players to say something about themselves.

A Well Matched Enemy

Players look for opportunities for their characters to succeed. They typically want to do what they can to avoid the death of their character. Naturally, ambushes against a well matched enemy are one way to increase odds of survival. There is still room for things to go sideways, but if the players earned their advantage there is nothing wrong with giving it to them. Like the previous example, there is the attrition angle to add tension. However, things could also change from being a situation where the entire party is at risk of death to where one or two players might die. However, for a player that doesn't want to be one of the “lucky” ones, that could be more than enough to make things tense.

Overwhelming Odds

One of the coolest situation an ambush can bring is the part where overwhelming odds become conquerable. However, it is difficult to get right. The encounter can be tough but not hard enough to really give the massive feeling of accomplishment at the end. It can also be truly overwhelming but remain so even with an ambush in place. This may not necessarily be a problem, if the objective is specific and not to simply kill the entire enemy force. However, this still provides a similar problem. How do you make the objective super difficult to complete normally, but possible with an ambush? There is also a criticism that I think is quite fair. Isn't this a bit railroad-y? I mean, I may be assuming the correct way to approach the encounter.

If the only way to get past the encounter is an ambush, I would agree. However, if an ambush is one of many possible routes, each with their own dangers, things look far better. Of course, some ideas may need to be hinted and seeded to give your players somewhere to start. And if they arrive somewhere other than you envisioned from those seeds, even better. No railroad there.

A classic situation is a large group of enemies. These enemies can be dropped in a single not lucky hit. However, their sheer number makes them difficult to fight. In the case of an ambush and a surprise round (assuming 5th edition D&D rules), you can reasonably estimate how much will be left afterwards. This essentially means that the encounter we are designing is the one after the surprise round, but the free hits can make thing seem more impressive when not overused. This might not be enough to make things even. Only by using the environment or some other factor do things finally fall in line. The issue is that unlucky rolls leaving more enemies than expected after the surprise round will mean the encounter remains impossible. 

A Monster Ambush

Weak Monsters Strike

Surprise is a powerful tool. A weak enemy could be made formidably or at least worrying for a party through this technique. Imagine a party of level ones going through a forest. One wolf isn't much of a threat. However, if it has the chance to dart out of the trees and strike a target of its choice before being noticed, it becomes a threat. Not to the party, but to an unlucky PC who doesn't want to die. This can be further expanded by using non-standard tactics.

The most classic encounter to mix things up is the stealth attack encounter. Some creature coming out of the unseen shadows and attacking a player before retreating back to where it can plot its next move. With this advantage of stealth to return to, it can continue being difficult to fight. However, some creativity (readying an action for when it flies into the light of the torches or to light torches and throw them into the darkness to leave no room to hide) makes things no longer a challenge.

Formidable Enemies Strike

Giving a surprise round to a group of well-matched enemies has the potential to go very badly for the PCs. Some might die or be dropped before even having time to react. We DMs just live with this fact for our NPCs, but players often don't like it. After that, they then need to find some way to pull a win or at the very least avoid a loss. It isn't a good situation to be in.

Having said that, it is manageable. The party just needs some way to bring things back in line. It could be the use of an item, it could be clever terrain use, it could even be the assassination of the leader. It could also be the not very honorable but practical retreat. However, throwing them into a situation like this without a way to get out can rub players the wrong way. The exception is if players did something dumb. If it's their fault and a stupid decision in the beginning, or they knew what they were possibly getting into, it tends to go over better. However, it probably shouldn't be an instant total party kill if we want things to be fun. There should be a risky escape possibility or at the very least grant them one if they think of something clever.

Ambushed by Overwhelming Odds

I can't remember the last time I've seen this situation. Maybe this could work if your players did something stupid and they are in a campaign where death doesn't mean as much (revenant campaigns rock). It might also work in very specific cases. If killing the necromancer makes all their skeletons crumble, it could work. However, this situation's difficulty is already changed due to this condition so I'd argue it isn't overwhelming odds. However, generally I'd say avoid this kind of thing. If you are even thinking of this one, you should have a good reason and be cautious. The already overwhelming odds just become more so  when they also have the element of surprise.