Legion came back from my first reader, with a delightful range of scathing comments but that’s how we get things done.
I don’t think I’ve ever ended up editing same story quite as much as this one before, but it’s helped me get my editing process down. If I have some overall doubts about a story, I produce on a separate document a summary of who each character is as a person. Then when I go back over the story, at each scene I consider if the character is demonstrating that personality in some way (short stories need to be concise). It’s surprisingly easy to throw in characters who are essentially living plot devices and forget to give them any sort of actual character, or have characters who have wildly varying personalities based on my two different interpretations of them on different days of writing. This method helps me check the characters are consistent and interesting, and provides a reliable method of checking my own work (something it can be difficult to do).
My other main method of editing I’ve realised is skim reading. After I’ve given the draft one or two rewrites, I reread the whole story very quickly, intentionally not checking every word. Often it helps to say the words quietly under your breath. If you deliberately read it quickly and loosely (something its surprisingly hard to do) I find your brain has a tendency to say each sentence exactly as you meant to express it, rather than what you actually wrote. Sometimes the difference can be significant. I’ve lost count of the number of grammar puzzles I’ve been able to solve using this method.
Editing is hard, and unfortunately it seems it can just fail sometimes. I’ve had occasions where I’ve read something through over and over, convinced it was good, and been told it was in fact full of mistakes compared to previous, more quickly produced work. Evaluating your own performance is difficult in almost any field, purely for psychological reasons. My one solid advice would be that when you do have a passage totally right, you can usually tell. If you’re unsure about something, you may need to take major steps to fix it and it could take some time.
I guess the pros just produce top quality work as standard after so much practice.