International Student IB Diploma Junior applying to top tier schools

<p>Hi guys, this is my first post so sorry if I sound wrong or anything. I just wanted to know how can I improve my chances to go to a top tier school in the US like Stanford, MIT, Caltech, UC Berkeley, Cornell, etc..
I am an international student from Korea but I have been in an American school all my life. Also, I'm finishing my first year as an IB Diploma student as a junior. I have a 4.02 GPA uw. The bad thing is that I got a 2020 in my SATs (2nd attempt). I'm doing a third try to improve that grade, but it doesn't seem so happy on that note. As an IB diploma student i have to do 150 hours of community service, action and service. I have been on the varsity basketball team for 3 years and I play the guitar and flute for more than 5 years. I have gone to various competitions but i haven't won anything... I'm about to take my SATII on Math II and Chemistry. I think I could nail around 750 in each. However, people tell me that it is very competitive to enter the schools mentioned above. I also have a couple safeties like GeorgiaTech, U of Michigan, UIUC...
Can any of you give me some advice on improving my chances this last year to get into one of those schools? My first choice would be Stanford.
Thank You!</p>