There’s many things you have to do when editing a novel. Considering things like grammar, sentence structure, etc etc. You have to begin to make decisions about what you want to do with it. What kind of shape do you want your novel to look like? Is it a square? A triangle? Are you jumping all around in verb tense? Is that important to the story? Are you a minimalist? Or a maximalist? Do either of those decisions make sense to your story? Reconsider the names of some of the characters like Tom and Jerry. Is there symbolic significance to them and is that the sort of subtext you want? What’s the implicit message? Are you repetitious? Are you saying the same thing over and over again? Are you using different so things don’t get stale quickly? Are you bringing depth to what you’re trying to say? Are you making new connections? You scour every paragraph for a meaning you might not of meant. Then you come to a decision.
The first big decision I made editing wise is verb tense. There are some things you just can’t do in the past tense that you can do in present and vice versa. When I wrote the rough draft. I threw ideas as they came to me. Whatever came to me. I didn’t exactly unify the tense. Choosing one or the other would limit certain perspectives. I was anxious about it because I just wanted it both ways. But when you come to the editing phase you make a decision. That’s the only way that there will be progress towards finishing anything.