Nick Mamatas, controversial writer and editor, was asked by someone whether or not they had the potential to be a great writer. He posted his answer and it's a fascinating discussion of good versus great, the value of practice and turning on the pilot light of imagination.
The whole answer is worth reading and debating, but I wanted to point out one particular bit because I think it has a universal truth that applies to all creative work.
The goal of the practice is to negate the negation -- to eliminate the use of other people's imaginations instead of your own. You must negate and negate and negate until there is nothing left but you, your right hand, and that woodchipper. Do you think it is clever and responsible to find "balance" in your life by keeping a day job and writing every other weekend? You should cultivate a loathing for yourself, for such advice, and for the pathetic circumstances of existence -- bills and kids and private property, that makes that advice seem so sound. Do you think "real artists" run around from lover to lover, living off the fat of the land and friendly patrons one might meet in midnight cafes? Embrace the reality that you are a hopeless poseur playacting the neuroses of a couple prominent writers and zillion awful pigs from the last century. All that has come before is worthless, except for those few people you realize were using their own imaginations and not the mass imagination, and their work.
As you can see, Mamatas is not out to make any friends. Even if you disagree with him, what he says is worth thinking about. How much of what you do is just you? How much is just everything that came before you projected on to you? What do you need to do to grind away the inessential, unoriginal parts of your creativity?