I'm 16, and a guy, about a month ago I made a friend who's 17 and a girl. Right now she's my only friend...
a) share food with her (I hear it dates back all the way to the time of the neanderthals, and is still effective
b) share a drinking cup with her
c) tell her "well, don't you look lovely...?"
d) (she said her little brother was her 'Knight in shining armor') so I tell her, "I wanna be your knight in shining armor like your brother is," with a smile