Stay in contact with the admissions office. This does not mean you should pester them, it just means that you should let them know that you are still interested. Being waitlisted by a graduate school is not the end of the road, see it as a bump, and handle it that way.
Talk to someone in the admissions office, personally. Find someone in the office that will communicate with you. It will most likely be someone assigned to your area, and write them about your sincere passion for their program.
Keep them in the loop. As you continue to make strides academically, let your contact know about it. You can continue to build on your application this way. Include any news coverage that includes your name and accomplishments.
Have an important person in your life write another recommendation. Pick someone who can sell your personality traits and drive to succeed in their program.
Be tenacious. Keep in mind throughout this process that you are worthy of their program, and that you deserve to give them a chance to recognize that you should be a desirable candidate. Handle being waitlisted by a graduate school by marketing yourself in the best way possible. Go at your marketing campaign with this attitude, and it will show through to their office.
Try again. If your attempts at getting moved off the waitlist for that application process don't pan out, keep moving forward. Reapply when their process allows, and make sure that you have improved your application to the point that you can't be rejected or waitlisted again.