Refining
After you (and your test audience) have reviewed the rough cut, you are most likely in for a long series of changes.
The entire film may have to be re-edited, with new shots substituted and whole sequences re-ordered. Generally, the next cut will be shorter in length, with those shots and sequences that did not contribute to the entire effect eliminated.
Sometimes the director has to lose some favourite sequences because they were not necessary. If you’ve ever watched deleted scenes on a DVD, you will see that many pieces fall by the wayside in the late stages of editing. You’ll also notice that there may be very good reasons why these scenes were left out of the final film.
Now the sound editor goes to work: covering dead spaces in the soundtrack with ambient sound, smoothing the blend of sounds and balancing the levels. Music may contribute to the emotional colour of certain scenes, becoming a kind of subconscious cue to the audience about how to feel about what they are watching.
Finally, sound experts perform a final mix of the sound, to balance volumes and smooth transitions.
Trim the fat!
http://vimeo.com/videoschool/lesson/84/trimming-the-fat