One of the slowest ways to write is to do it with your reader looking over your shoulder. The audience, editor, supervisor, or colleague in your head can easily become a powerful judgemental voice that slows every sentence and questions every word. If you never want to finish something, edit as you go, like Penelope unweaving every night.
For quicker progress, give yourself permission to write messy drafts. Don’t rephrase, find just the right word, fiddle with commas, check references, move paragraphs around, etc. Get the bones down first and save those things for later. Build the muscle that lets you draft without judging what shows up on the page.
By doing this, you give yourself the gift of something to work with. You get a half-baked idea down there so the fully-cooked one can follow. It is almost always easier to sit down and revise than it is to face the blinking cursor on an empty screen. And, you will get more written if you are not constantly stopping along the way because that internal critic is telling you something is not quite right. Or course something’s not quite right! That’s the whole point of a draft!
No one needs to see an initial draft but you. You can call it a zero draft, if you like, not even a first draft. You can call it a down draft, the one where you’re just getting stuff down. You can call it, in the immortal words of Anne Lamott, a shitty first draft, if that helps you lower the stakes and get on with it.
When your creative brain is hard at work, when you’re generating ideas and connecting facts and figuring what it is you want to say and how it fits together, don’t let your tidy-up brain get in the way. When you’re drafting, just draft. The crafting can come later.