From The Paris Review Interviews (volume 2) this advice from William Faulkner; advice that should be drilled, with military precision, into the heads of every creative writing student in the UK – and most of its published writers as well.
Interviewer
How does a writer become a serious novelist?
Faulkner
Ninety-nine percent talent… ninety-nine percent disipline… ninety-nine percent work. He must never be satisfied with what he does. It never is as good as it can be done. Always dream and shoot higher than you know you can do. Don’t bother just to be better than your contemporaries or predecessors. Try to be better than yourself. An artist is a creature driven by demons. He doesn’t know why they choose him and he’s usually too busy to wonder why. He is completely amoral in that he will rob, borrow, beg, or steal from anybody and everybody to get the work done.