How can I get him to notice me..?

i'm 14 and i really like this guy, the only thing is - he barely knows i exist. he sits behind me, but tomorrow's the last day of that class! and i doubt he'll be in my others! he's given me a nickname, and i talk to him sometimes on facebook but i'm always the one starting the convo. he's got exactly the same sense of humor as me but i get really shy around him. what can i do? julie :)