I sent an update/interest letter telling the school they were my top choice (it was true in my case, although I suppose you could just say that 🙂 ).
If you know of any weak areas of your application, perhaps try to highlight them. For instance, I knew my clinical experience was lacking. So in my letter I described some of the clinical experiences I'd had since my interview.
I don't know if that helped or not, but I'm sure it's worth a shot.
Good luck...I'm sure you'll hear something soon!