Self-editing has been terribly painful for me. Rather than being able to sit back and look at the content critically, I find myself being drawn into the plot and I forget to edit. (However, I think this is a good thing, since I still enjoy the story after two years.)
I've developed the practice of opening the pages at random and attacking the page, paragraph, or sentence that reads rough in that particular sample. Then I read a larger segment to make sure the entire passage makes sense.
BUT I'm still not finished; I go back and reread my corrections the next day. If I still like the change, I keep it. If not, I repeat the process until I do.