But one way to get started on that dreaded second draft is to refer back to the outline, mental or otherwise, that you made before starting to actually write your novel.
Does what you actually wrote fit what you planned to write? Did you succeed in staying on task? Did you say what you wanted to say? And so on with whatever questions are right to ask about your own story.
If something strayed from your original intent, was what you said better than what you thought you’d say? If so, then redo that original plan and then make sure that your new, revised story fits your new, revised plan. Mark places that need changing so the story as a whole fits the new, revised plan.
If your original story is what turned out to be right after all, then does what you wrote stick to that plan? If not, then make notes of which parts need to be changed.
This isn’t an exercise in futility. It’s a way of making sure your story works and moves forward smoothly. And it doesn’t require changing a single word. Yet. (That will come later, on rewrite number 3, when you do the same thing with each chapter, and then each scene, and then each paragraph.)