MIT is by far the hardest school to get into the western world, at least in a general sense. Their international acceptance rate is somewhere between 1% and 2%. Oxford's is 18% (for UK students). Granted, there's no limits on applications in the US and you can only apply to 5 here, but other competitive schools, like Harvard or Yale, have acceptance rates 3-4x higher.
Now, onto the actual stuff. You need the SAT/ACT and 2 SAT II Subject Tests, one of which has to be Math II and the other a science (Physics/Biology/Chemistry). You'll need perfect grades too. But what you really need, and what I suspect you might not have, is a strong set of ECs with an obvious spike. A spike is a trend across your ECs that shows a strong, continual interest and leadership in a certain area. A good example would be hiking: if you do DofE Gold, run scouting expeditions for young kids, and campaign for greater outdoors funding in schools there's an obvious spike.
Someone I know who got accepted to MIT is a Peruvian immigrant who moved to the UK aged 14. He didn't know English and ended up getting 9s in everything within 18 months. I wish I was joking, there are genuinely people this smart.