Line by Line Editing:
This is where you go line to line, chapter to chapter making sure that chapters, paragraphs, and sentences say what you want them to say in an understandable manner. Make sure that the points that you are making are clear. Can be done in the next pass.
Listen to your work:
There are programs out there that will read back what you have written, and some E-Readers do as well. Failing that you could read it out loud, notice where you change up what you are reading (as we do sometimes), then make a note to change accordingly. I suggest this because sometimes the only way to catch something that you have read and reread quite a bit, is to listen to it. It may not work for you, or even me, but if you can give it a shot and see, especially if you are stuck.
Make sure all your plot links are added, and followed through on, make a note of any that need an end, or you had forgotten in your work.