A few things I've learned about editing your own work, mostly by doing it badly for years and then reading people who'd thought about it more carefully than I had.
The six-week gap between drafts exists because you need to forget what you meant to write
Stephen King, in On Writing, says to finish a draft and then put it in a drawer for six weeks. Minimum. He's specific about the number. And when people talk about this advice, they usually frame it as "getting distance," which is true but vague enough to be useless. The distance isn't the point. The forgetting is the point.
When you finish a draft, you can't read what you actually wrote. You read what you meant to write. Your brain fills in the gaps, smooths over the clunky transitions, supplies the emotional beats that never actually made it onto the page. You read your intentions, and your intentions are always better than your sentences. King understood that the only way to break this is time. Enough time that when you open the manuscript again, you've lost the memory of what you were trying to do in any given paragraph, and you're left with what's actually there.
This is the same reason you can't proofread an email you just wrote. Your eyes skip over the errors because your brain is still running the version you meant to type. Six weeks is King's number. Yours might be different. But the principle holds: you can't edit from memory. You can only edit from the page.
King also has that formula: "2nd draft = 1st draft minus 10%." Which sounds like a math problem, but it's really a permission structure. It tells you, before you even start, that the draft is too long. That something in there needs to go. The question is never whether to cut. The question is where.
Your first draft is supposed to be bad, and treating it otherwise is the problem
Anne Lamott's "shitty first drafts" chapter in Bird by Bird gets quoted so often that I think people have stopped hearing what she's actually saying. She's making an observation about what first drafts are for: they exist so that something exists. That's their entire job. A first draft is raw material. It's the block of marble before anyone picks up a chisel.
What Lamott noticed, and what I think is the more interesting point, is that perfectionism during drafting is a form of editing before there's anything to edit. You're trying to polish a sentence that doesn't have a paragraph around it yet, that doesn't have a structure to live inside, that might get cut entirely once you figure out what the piece is actually about. She calls perfectionism "the voice of the oppressor," which sounds dramatic until you've spent four hours on an opening paragraph and then deleted the whole section the next day.
The first draft has one job. After that, you can be as ruthless as you want. But you can't revise something that doesn't exist, and perfectionism is very good at making sure nothing exists. Lamott knew that the hardest part of editing comes earlier: having written enough bad pages to give yourself something worth editing.