Studying, from life and from books, the internet. And loads and loads of practicing. Painting, painting and more painting. If you do that, you'll get better! That's what I've noticed the past year or two anyways.
Nope, I have just studied on my own. Yeah probably, just the drive to get better is what is pushing me the most I think. Getting inspired by other artists and wanting to become as good, if not better.