Most unfinished writing is not abandoned. It is polished to death in the first third, where the sentences are easiest to fuss over and the hard structural questions have not arrived yet.
A first draft has one job: to exist. Everything you like about finished writing happens later, to material that is already on the page.
Write forward only
No editing above the cursor. If a paragraph is wrong, note it in brackets and keep going.
[fix this, the timeline does not work] is a perfectly good sentence to leave in a draft. It takes two seconds and it protects momentum, which is the only genuinely scarce resource in the whole process.
Stop mid-sentence
Hemingway's trick, and it survives because it works. End the day's work in the middle of a line you already know how to finish.
Tomorrow you sit down with a running start instead of a blank page, and the blank page is what kills drafts.
Nobody has ever been blocked halfway through a sentence.
Set a floor, not a ceiling
Three hundred words a day finishes a book in a year. Two thousand words a day finishes nothing, because you will miss a Tuesday, then a week, and then it becomes a thing you used to do.
Make the floor embarrassingly low. Low enough that skipping it would take more effort than doing it.
Then leave it alone
When the draft is done, put it in a drawer for a fortnight. You cannot see your own sentences until you have forgotten writing them, and revision done too early is just typing with anxiety.
