How to talk to him?!?

Ok there is a boy at school and I have a huge crush on him. Saturday was prom and I got weak kneed when I saw him I was so happy, and I was more happy when I noticed he had not brought a date. I watched him for a little bit I think we might have made some eye contact. I wasn't staring him down like a stalker lol. But I was hoping he would ask me to dance. Cause I am way to shy but nothing happened and I left prom regreting not asking. But I want to know how to strat a convo with him, should I add him on Facebook and start chatting , I mean we have alot in common. And he is such a good singer :) I really want to get to know him