How to become 'alpha' of the clique?

Well I'm what I guess is a 'beta' and so is my other friend Tia, and the 'alpha' of the group is Kathleen. She's ALWAYS been alpha and it's really annoying because she's really up herself and always makes little snide remarks about me and Tia. I'm fed up of being a stupid little follower and I want to kinda swap the arrangements round a bit. I try to stand in the middle of Tia and Kathleen but then Kathleen manages to wriggle her way into the middle and then try to exclude me a bit. Overall Kathleens a very good friend but I really don't like her being alpha... How can I boost my self confidence and slowly wriggle my way into being alpha? Thanks (: Also, don't waste your breath if you're going to say that cliques are immature... I'm just a kid, if I can't be immature now, then when can I?! (: Also, I don't want to be alpha just to show off, I actually want to stop getting bossed around by Kathleen and feel a bit more confident about my self (I have self confidence issues)