Notice where you and your friend that everyone likes are different, and emphasize those differences. If you’re athletic and she’s not — go out for a sports team. If she’s athletic and you’re not, get involved in Student Council or music. Don’t make up differences, but where they do exist, emphasize them with your own special style.
Most importantly, know that you’re a winner and act like one. The worst thing you could do would be to act like second best. That’s why it’s a good idea to work on your individuality.
As for your friend’s popularity — watch her and see what it is she does that boys like so much. You may learn something from her. Also, tell her how you feel — in a friendly way. She may not know your feelings, and if she’s a nice person, she may be empathetic and helpful. If she’s not a nice person, well, then, you be the nice one! Boys (the ones that are worth dating) love nice girls.