Unfortunately, my lack of details is often due to laziness. I have the picture of my story (or adventure) in my head, but I don't want to take the time to put it all down on paper. The problem is that if I don't write it down, at least as a note to myself, I often forget those details myself, and thus I don't get to share the richness of the world that I have created.
This has become much more apparent to me this summer both in my reading/writing and in my playing/DMing. I have noticed the lack of detail in my own endeavors by comparing it to the richness in other people's. I have also noticed other people's reactions to the detail--when does it seem like too much? when are they getting "swept away" into the world? etc.
As such, I have tried to place more detail into what I am creating, but much of it has been ringing false. It feels contrived or forced. I can't tell if its because of how I am expressing the details, or if it's just my natural reaction to trying to do more work (which is to avoid it).
The key is hitting the right notes: the perfect images, sounds, smells, and impressions that a scene can hold. Right now, I feel like I'm blindly hitting notes in the hope that something beautiful comes from the attempt. I suppose, like most things, it's a matter of practice and experience.