<p>My two cents:</p>
<p>Rejected: I would say to let it go. They picked a large number of acceptances, more than they intend to admit (list A). After that, they picked a larger number of waitlist kids, that they can pick from when their acceptance offers are rejected (list B). If you didn't make either list, you will not be getting into their school. However, if you do intend to apply again, politely ask the reasoning behind your rejection (phrase it as, "Could you please tell me what areas need improvement, so that I can be stronger on next year's application?")</p>
<p>Waitlist: Definitely call and let them know they are your first choice. Also ask what you can do to help your chances----send in more grades as they show up, get another letter, etc. Ask if there is anything else they need from you. Again, stress that they are your FIRST choice, and say WHY that's so. Be incredibly polite, keep the conversation short and to the point, and be absolutely sincere.</p>