Like Eliza said, start out with just saying "Hi" then try to get to higher ground, and starting a conversation. That's usually how you get to know a guy better.
Your welcome ^_^ and dont show your shyness or how nervous you are, some guys think its cute, and some dont, so yea just act nuetral, be cool around him. Dont over due it either cus thats kinda weird AND uncool O.o but act like yourself, dont act like something your not just to try to impress him. To make it easy, start smiling at him, make eye contact, good eye contact, not flirting eye contact cus he might think its weird. Also notice him, and connect eyes with him, make it simple, then you can go to saying hey or hi when he passes by, he wont think its weird if he's seen you before. Then go on with more down the line :). Sometimes you need to just get that out ^_^.
Well why dont you start off with a 'Hello' or 'Hey whats up'. Or if your friends with his friends and he's around, and your all talking about a specific topic why dont you ask for his opinion on something, whatever you guys are talking about? Just start with the basics, like a hi or something, then you move on to more of a small talk, then you go on with trust and confidence, keep that door open for him to be confident around you.
Also be yourself, let him see who you really are, and be nuetral if your good at that. But yea you can start with a hello and just move on to more later, and who knows maybe you guys will end up I dont know, with something special, but for now just start with the basics :). Dont stress over it ^_^.