What should I do to make a mark?

I am 15 (almost 16) years old, and I have always wanted to do something significant. I always wanted people to be able to say, look at her, she is really good at that, or look what she did. (In a good way!) I am not particularly amazing at any one sport, I play lots, but I am not a superstar like some of my friends. I get pretty good grades too, but nothing remarkable. What should I do to make my mark?