A good Dungeon Master is able to bring a location to life. An important part of doing so is to provide details on locations. However, especially for new Dungeon Masters, it can be a challenge. For that reason I hope to cover a few basic tips that should help make bring locations to life and make them memorable.
Other than Sight
I tend to fine just about every Dungeon Master I've played with is able to describe the visuals of an area. There may be some details left out that would have really helped to bring the location to life, but the visuals of a location will still be explained. However, I find that sound and smell are often left out. Temperature can be very important too but I find this is usually handled brought up when dealing with extremes but not mentioned when going into an underground cavern.
How Much to Describe?
You don't want to spend too long describing a room because the game has to keep rolling. Also, keep in mind that the players can ask you questions about the location. However, I try to make sure the visual aspects of the room are described (if you use miniatures, the grid and map layout help greatly) because they are incredibly important to combat considerations. Light and obscurement are also important here so that you and the players don't forget about any bonuses or penalties they may have from these factors (these factors also don't appear on the board if you forget). However, I also try to describe noteworthy sounds or lack of them as well intense smells. These other elements are extremely important when they act as a warning to the players (noises and a foul smell coming from the other side of the door).
Forgetting to Describe Changes
One problem I've seen is that certain senses will get attention in a certain room (rotting smell) but won't be addressed when you move into another room. In my case, my players understand that if I don't change my description, the sound or smell is still present unless it doesn't make sense (if you travel away from town and into the forest, you won't hear crowds anymore). However, your players might also assume that if you don't describe a sound or smell, it is neutral. It's important that the Dungeon Master understands what their players assume and treats them accordingly. For me and my players, having to think through this can break immersion. It's also generally good to establish an understanding with your players so that they realize sometime you may forget and they should ask if they aren't sure.
One of the most memorable things for my players is transitions. How does the room come to life when the light of their torches peels back the dark? Does something reflect the light back (reflections can create uniqueness by themselves)?
Aim for One Unique Thing
I try to make sure that one part of my dungeon or session is something unique my players will remember. There can be obvious parts such as a shocking plot development or a challenging fight. However, it can be a weird and unique room that captures their imagination. One example I can think of recently is that there was a room we entered that was brightly lit but where nothing cast a shadow. It's those kinds of descriptions and unique details that can etch themselves into the memories of your players.