I'm finally done. There was no secret to my score. I took months of self-study, and even went through two prep courses (Veritas Prep and Manhattan GMAT). If anyone is at all interested in these prep courses, I have actually written up a pretty comprehensive head-to-head analysis of the two. You can find it here:
http://tmmycgmat.blogspot.com/
If it is a bit long for your taste, you can scroll to the bottom for the summary, or to whatever section you find most relevant to your situation. Good luck everyone!