Most Helpful Guy
Flirt, hun, just flirt. Talk to him, let him know you enjoy his company and you enjoy talking to him. Ask him to casually hang out, and be enthusiastic to see him. It doesn't have to be a date, but spend some time together and see where it goes. And make sure no one else tags along. Do NOT ask other people to come, or initiate a group hang out.
I think the most obvious hint is to initiate physical contact, and see how he responds. Just touch his arm or hand, try to stand near him. Casually brush his shoulder as you're talking to him. And eye contact. If a girl is always not looking at me, I would assume she's not interested in what I have to say, or me as a person. Hope that helps.