Since I was at NYU, I can tell you that you get brownie points for a thank-you
card or email, and more brownie points if you tell them they are one of your
top choices (or even #1). Beyond that, there's nothing else you can do to help
yourself, at least, not at that program. Additional phone calls don't help, and
extra emails or cards don't help either. Taking a second look will not help.
Don't know how much of that holds true at other institutions, but for what it's
worth, that's how it is at NYU.