First of all what is your GMAT as compared to the average? And if you are over-represented is it 20 over the average? If not this is kind of an invitation to retake the GMAT.
If your test score is on point, have somebody review your application who is a professional. Doing this yourself is very unlikely to get at the answers because a fish doesn't know what water looks like.
The good thing about this is that it will help you shape how you need to approach your waitlisting effort, and also inform your approach for future applications.
Likely there's a problem with your application meaning the recommendations or essays, CV, or your goals, and often a good way to remedy this is to offer more evidence of your leadership ability something like that. What you'll want to do is create an update letter, you don't want to rewrite the essays that's going to undermine your credibility quite a bit.... take a targeted not comprehensive approach.
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