I might have mentioned this before, but I think having someone read your work out loud to you greatly helps the editing process. My wife reads my work to me, and it seems to be the only way I ever catch words or phrases that are repeated in proximity or used too often.
Also, it seems easier to challenge the logic of the story's construction. Somehow, when another person verbalizes the story, it comes across fresh and new, giving me, as the writer, a new perspective, and I tend to be more critical when listening. I might say, "That doesn't really work, does it?" and I have a chance to make it better.
For some reason, this process doesn't work if I read it out loud to myself. I don't really hear it. It's almost the same as reading it in my mind. Hearing my wife read adds another benefit. I get to hear her lovely voice.