Be yourself. Be friendly. Be kind to people. I like to say, to have a friend, be a friend. You'll be popular with someone. Don't try to be overly impressive, because people see through that pretty quickly.
The first step to being popular is having confidence and willing to step out of your comfort zone. You also have to be friendly to your peers, teachers and everyone else. You can visit thinksimplenow.com/relationships/the-popularity-factor/ for more tips.
Depends on what your definition of popular is? Do you want to be popular in the newspaper, then bring a gun to school, if you want to be popular with your friends, then that's a lot harder to accomplish, my advice is just be happy with yourself, because you'll discover the hard way otherwise, that living up to other peoples expectations is very costly.