isaacycc, firstly let me say that being waitlisted is kinda good sign. You should contact the ad com to reiterate your interest and then they will assign you a w/l counselor. that will take about 10 days. after that, the counselor will tell you what are their concerns and you should address this issues with additional essays. then show them your progress or interest by direct contact, either through email or phone calls, to the ad com from time to time (but, really, don't be too often). after that you can just wait.
good luck for both of us and hope we can meet on campus this fall!