I'm 17 years old and I've never had a boyfriend. how do i get one?

I go to an all girls school and its really hard to find boys to talk to. I really want a boyfriend before i graduate. How do i talk to boys? What do they like? How do i branch out of the small social scene i'm in. it seems like every boy already has girlfriends and nobody is interested in me. Please help. im desperate. no snooty responses plz