I always draw/paint my own backgrounds, I think it's kind of a bad habit to "borrow" them. Anyway, best thing I can advise is to learn perspective. There are lots of good books about it, and that is the first and foremost foundation of a good background (though I didn't show it so much in this particular pic ). Once you've got perspective down, the rest falls into place a lot easier. Draw and paint from life, too, it always helps.