Wise words from Real Live Preacher, one of my favorite websites. The whole piece (though short) is good, but here's a tidbit:

If you want to write you must have faith in what is. You must respect what exists, because it has earned the right to exist. Of all the possibilities, of all the things that might have existed, this thing exists and you should write about it. Be fearless. Explain nothing. Justify nothing. See things as they are and write about them. Don’t waste your creative energy trying to make things up. Even if you are writing fiction, write the things you see and know.