Description is what makes the reader a sensory participant in the story. Good description is a learned skill,one of the prime reasons you cannot succeed unless you read a lot and write a lot. It's not just a question of how-to, you see; it's a question of how much to. Reading will help you answer how much, and only reams of writing will help you with the how. You can learn only by doing.
The most important things are the hardest to say. They are the things you get ashamed of, because words diminish them -- words shrink things that seemed limitless when they were in your head to no more than living size when they're brought out. But it's more than that, isn't it? The most important things lie too close to wherever your secret heart is buried, like landmarks to a treasure your enemies would love to steal away. And you may make revelations that cost you dearly only to have people look at you in a funny way, not understanding what you've said at all, or why you thought it was so important that you almost cried while you were saying it. That's the worst, I think. When the secret stays locked within not for want of a teller but for want of an understanding ear.