Flirting tips for camping and beach parties..?

Hey, so there is this really cute guy that I like. I've known him for five years as we are in the same year at the same school but I have only talked to him about twice. My friend is emmigrating soon so myself and friends are planning on throwing a camping party for her. The friend I'm planning this with hangs out with him and will probably be inviting him to come along with his mates too. I just want to know how to flirt with him subtily. We're both sixteen and know each others names and it wll have been my birthday three days earlier so will that help..? Also he added me on facebook like two months ago.. so do you think i could start a convo with him on that or would it be weird? Thankyoou.