[This started out as a comment on this post by Phillip McCollum. Then I couldn’t post it for some reason, and I realized it was really too long to work as a comment anyway. But you should read Phillip’s post before reading this.]
The big mistake I initially made when I started writing fiction was not doing enough description. I’ve talked about this before, and how it took my friend Pat Prescott repeatedly encouraging me to do more description before I finally got the message.
In my arrogance, I thought that description was boring and a waste of time, and that I was a genius for not doing it. But description isn’t boring—only bad description is boring. Done well, it seems like an integral part of the story.
There are probably other ways that I’ve gotten better at writing over the years, but this is the one that comes immediately to mind. And I want to stress that it was only because I was lucky enough to have a reader like Pat who would tell me (more than once; kudos to him for his patience) that I needed more description. If not for that, I would probably still be blithely bumbling along, writing stuff that contained no description, and thinking I was brilliant for doing so.
The real point here is less about description than about listening. Listen to what your readers tell you. A reader who is willing to comment honestly on your work is the most valuable thing a writer can have.