What are somethings i can do to get in Harvard?

[Ik]

You are starting quite early, which I think is a good sign.
Firstly, don't get stuck to Harvard. It's a good university, but there are other really good universities too. And each of them has a personality, a style of working. Find the one which suits you best. You don't want to go to Harvard and be unhappy for four years. I would suggest don't think about any particular college now, because you are relatively young and your choices and tastes may differ in the next four years.

Ok, now things that you could do from your next year. The main thing is enjoy your high school. Do things that you like and do them with energy. Don't go into clubs that you don't like, just because you think they will look good on your application. Don't try to be an allrounder, because nobody is. Do few number of things, but do them passionately.
Grades are important, however, more imporant is growth. It doesn't matter if you are bad at studies right now. Keep on improving. Don't burden yourself with really heavy courses. Challenge yourself, but not too much. And you need to show that you have taken a variety of courses, like Math as well as Political Science, but again, choose those which you like. If you don't like something, it will show on your application.
Be nice to teachers, because they will give recommendations.

You are right, universities will look for one trump card you have (in academics and extracurriculars). Don't worry about it, you will come to know of it in the next two years.

The main thing is this, don't do anything for the sake of applying. Simply work hard and enjoy.