From Bird by Bird: Some Instructions on Writing and Life, by Anne Lamott:

“People tend to look at successful writers…and think that they sit down at their desks every morning feeling like a million dollars, feeling great about who they are and how much talent they have and what a great story they have to tell; that they take in a few deep breaths, push back their sleeves, roll their necks a few times to get all the cricks out, and dive in, typing fully formed passages as fast as a court reporter. But this is just the fantasy of the uninitiated. I know some very great writers, writers you love who write beautifully and have made a great deal of money, and not one of them sits down routinely feeling wildly enthusiastic and confident. Not one of them writes elegant first drafts.

“Very few writers really know what they are doing until they’ve done it. Nor do they go about their business feeling dewy and thrilled…. We all often feel like we are pulling teeth, even those writers whose prose ends up being the most natural and fluid….

“The first draft is the child’s draft, where you let it all pour out and then let it romp all over the place, knowing that no one is going to see it and that you can shape it later. You just let this childlike part of you channel whatever voices and visions come through and onto the page…. Just get it all down on paper, because there may be something great in those six crazy pages that you would never have gotten to by more rational, grown-up means. There may be something in the very last line of the very last paragraph on page six that you just love, that is so beautiful or wild that you now know what you’re supposed to be writing about, more or less, or in what direction you might go—but there was no way to get to this without first getting through the first five and a half pages.”