Tips for novice builder?

[gedweyignasia]

So I'm trying to make a very small area. (Two rooms and a hallway. Probably a total of 30 tiles in area.) Aaand I'm learning that I'm very bad at it. Some things I make look cluttered, other are bare and open, and the entire place looks very sterile. I handed the module to one of our builders for tweaking to make it more player-friendly.

He gave it back to me after an hour or two of work, and it was full of a million details I never even knew I could put in. I'm trying to make a list of all the things I've noticed changed and trying to see the patterns to how he's set up all the placeables, but this is totally beyond me. Are there any tips or general guidelines I should follow to make my areas a bit more lifelike and enjoyable? I really want to be able to produce some content, but there's sooo much to learn. Should I just stick to scripting?