My experience, in writing 14 novels, is that I set a certain number of pages that I have to do every day, no matter what. For me, this is 5 to 7 pages, and they could drop the A bomb and I will do the pages. Sometimes, of course, or many times, I will throw what I write away.
Here is a link to my desk in the Atlantic Monthly.
https://www.theatlantic.com/entertain...You have to scroll down to see the pile of paper, but it is there.
I think, too, that the key to writing is the ability to tolerate imperfection. Most writers I know who give up can’t stand the idea that for many drafts a book will be a mess. They want it to be clean, clear and polished right away, and the only way that happens is by revising. Cold comfort, but there you have it.