US News has an excellent column on steps waitlisted applicants can take when in college waitlist wasteland. Key elements:
- Interest: Show the schools you are interested. They want to know you will accept their offer of admission and that you are a good fit for their program.
- Accomplishments. Did you stagnate (or just goof off, a victim of a serious case of senioritis) after you hit SUBMIT on your last application. Big mistake. Show how you have continued to excel and achieve.