How do i talk to this guy?

so this guy that in my gym cl is AMAZING and i really really lke him but ive only talked to him once, and it was over facebook chat :P i get so nervous when i see him and a loy of other girls like him, he basically coud have anyone he wanted. but i really like im and my friends think i have a chance so do i need to put myself out there? and if so, how? im usually pretty outgoing btw, but just not with him so dont say just go talk to him like, what should i say to him