Alright, the following is based purely on my observations. Take it with a grain of salt and don't cry foul if it does not work for you 🙂 .
It depends on two things: how many seats there are in the program and how many FTDs actually apply to the program.
The easiest school to get an interview is perhaps Penn, but by no means you will have the greatest chance to get in... BU and NYU both have relatively large number of seats, so it seemed that you would have a greater chance.... Then, again, that depends on how many FTDs applys in a particular year.
In California, five schools offer the IDP programs and the seatings range from 12 (UCLA) to over 30 (USC). All five schools use bench exam(s) to screen prospective students, so if you don't have confidence in your hand skills, proceed with caution! Since the requirements among those five are quite similiar, the chance of getting into one vs another is quite similiar. In another word, if you get into one, you will hear calls from another..
Bottom line: get a good score (90+ in today's environment), acquire some experience if you can, write a decent statement, find a nice reference and apply ASAP (please, I have seen people asking for their chances one day before the deadline. While to be brutally honest, in a rolling admission process, the chance is pretty low.)