I've only actually truly edited 2 books in my life because I probably will never publish for real and while my first drafts are rough, they're not so rough they don't make sense so I have mostly stuck to one draft and done books. Though I do make notes of things I don't like/want to change as I'm writing it that way if I ever do get back to it and try to polish it, I have somewhat of a guide. Especially developmental issues since I think that's my biggest downside. I have all kinds of ideas that I start, but often forget in the end so it leaves little threads of nothing lying around.
The two books I did edit, I had a hard copy bound on Lulu that I got for winning NaNoWriMo. This allowed me to sit down and read the book as a reader and I made notes in the margins or crossed things out. It helped me quite a bit to get off the computer and not have the urge to change things as I read. And it gave me a nice memento of those books...that are now marked up to high heaven.
I do let the spellcheck correct me as I write because I'm dyslexic so I make a lot of interesting mistakes. Some will still slip through since my biggest issue with my dyslexia is word swaps (spelling the word right but using it wrong, even though I know it's not the right word for the sentence) and spell check just doesn't always catch those kinds of errors. In fact, it doesn't catch a good chunk of them unless they're homophones. Since I'm struggling to write anything right now, when I do finally sit down to write I'll re-read what I previously wrote and I'll alter things as I do that, but I don't really consider that editing.
I definitely wish I could afford a developmental editor for just one of my books because I think that's where I lack the most.