start studying for ur SAT II ... u need to focus on 2 subjects only cuz to get in u need 2 650s only ... also , if u have any relatives in ISB , send ur documents to them , if not then try and go there right after high school and get all the paperwork done personally cuz that way u can get it done faster .... good luck
p.s. hey rehan , i have quite a collection of the questions that other shifa ppl got on their step1 and i was thinking of starting a shifa qbank or something ... i'll do something about that next week after my exam inshallah