How do I become popular?

I've always had many friends but I have never been part of the cool group or the group of people that everyone wants to be around. I know that popular means just having a lot of people that like you but that is not how it is at my school. And being voted the most intelligent person at school doesn't help me. I know that I won't remember half the kids at my school in 10 years, but right now I really want to be considered a little bit cool. And the girls who are considered popular all used to be my friends but now because I stood up to them when they bullied another girl a couple years ago at recess, they all hate me. (I do know that one day I will be better off than them but I still want to be popular.)