she loves herself more than you love yourself. Ironically, you two are good friends might be because of this difference.
There has to be other reasons that she is more attractive than you are. But you can do something about this one.
Start working on loving yourself more, really feel the love. Others might love you more because of it, since they tend to treat you the way you treat yourself.
Your realtionship with her might change as a result, so tread slowly. :-)