The two major things I did---
1. Worked A LOT harder on my AMCAS. Anything that I spent more than five minutes of my life on went into the EC section. Got feedback on my essays, etc.
2. Maxed out on LOR's. My previous attempts I was convinced I would get in with no problem, and each school got the minimum number of required LOR's. This time around I had a total of seven sent out to each school.
I've gotten A LOT more interviews this time around. No acceptances yet, but then again, I applied MD/PhD this year so the process is understandably more competitve than before (more essays to write, more apps to fill out, and higher average scores and GPA's).