This is from BikeProf, who is a credible source because he actually finished a book draft!
The Hobgoblin's Rules for Writing
Write every day. At the worst, your typing will improve to the point that you can write more quickly than ever before. More to the point, though, writing every day will help in two ways: 1) you will nurture the sense that you are making progress; and 2) you will eventually generate a large stack of pages.
Do not revise. I cannot state this strongly enough. Do not look at what you have written until you have finished a draft. Trying to revise in the middle of things will send you to that circle of hell where you are paralyzed and cannot write a second sentence until the first is so perfectly written, so immaculately phrased, that writing all over the world will instantly become meaningless and superfluous in comparison.
Have fun. You are all big readers; you love to read. So writing is the production of joy. The production of joy should have some element of joy in it, or you're just not doing it right.
Daydream. For me, writing was nothing more than imagining an entertaining scene, seeing it play out in my head, and then describing what I saw. Daydreaming is fun and does not seem like work, and soon, writing a little every day did not seem like work either.
Don't think about your audience. This goes against something I usually teach my freshmen composition students, and, to a certain extent, it is not advice to be followed closely. However, when writing fiction, if you think about every reaction of the readers, and if you worry how your mom will react to the character who swears, then you will wrap yourself up in a sheet of neurosis so completely that you will not be able to write at all.
Write truthfully. Genres don't matter. Labels are for bookstores and not authors. If you really want to write erotic sword and sorcery fantasy novels, then write the best, most truthful erotic sword and sorcery fantasy you can.
Write who you are. This goes along with writing truthfully, but is more personal. You have a voice, so use it. Don't try to write in a voice that will not work for you. Those who try to be Hemingway ventriloquists usually end up sounding more stupid than Hemingway-esque, after all.