How well do you multitask? Can you, say, you write and edit at the same time? Or better yet, what about doing multiple types of edits at once? That one is my favorite because I certainly can't even though I try.
For example, while revising my second novel, I've been looking for missing scenes to round out the story and the characters. While I'm doing this, I am not editing for grammar or punctuation. I am not rewording for flow and to improve sentence structure because I can't do all that at the same time.
Trying to do so is a rookie mistake unless you are an undiscovered genius of have the brain the size of a planet. A better approach is to handle one type of edit at a time.
You can probably combine spelling, punctuation, grammar, and wording (copy edit stuff) in one editorial pass. But missing scenes and plot changes and characterizations and all those bigger items are probably best done separately.
I had this conversation with a writer friend of mine. She observed that in her attempt to write a novel, the end of the story was better written that the beginning. But she was so overwhelmed at all the things she would have to touch in order to fix it, at the time, she threw it all away. She fell prey to trying to do too much at once.
How unfortunate. The experienced writer knows this is going to expect and realizes that when it does, you go back to the beginning and revise in order to even out the story. Generally, I start with something simple and let it take me into the story. For example, on my last pass through my novel I was looking for missing scenes. I kept asking, "what are my others characters doing while the camera is focused on the scenes I'm reading? Do I need to show those actions?" If the answer is yes, I have new scenes to write. If the answer is no, I move on.
How do I know how to answer the question? Experience and intent. Since I am trying to show the actions of all my major characters, if a scene includes one of them and advances the story, it goes in. And since I now have a small stable of characters and show what they are doing is hard and time-consuming.
Notice I said major characters, not main characters. The story has five main characters and introduces five more characters that will be important later in other books. The new characters don't look important at the moment but they will be and I can bide my time before rounding them out since what's important is the story I am trying to tale.
None of since means, by the way, that the new scenes will survive a final round of editing. That remains to be seen. What happens now is I read the novel and see if it holds together. If it does, I start looking at the wording, sentence structure, and so on. If not, I make the adjustments I need to make. We'll see. But regardless of what happens, this novel looks to be on track for an end-of-year release.
Keep your fingers crossed on that one.