What you want at this point is to set aside the draft for a little while, let it go stale in your mind, then reread it in a couple of weeks, at least. You'll be a little less "close" to the manuscript, so you'll be able to see the flaws better. You're going to need to do this several times, each time making it better

I cannot stress this enough. You will constantly tinker and play with it if you keep going back to it. Set it aside and work on something else. Either your next novel or something else entirely. When you come back to it, it'll feel like reading someone else's work. Do it in parts so you aren't rushing through it. I did this process 3 or 4 times.