i agree with Ticktock, you need to express how you feel : ]
But then again, its good to keep them guessing as well. Maybe just drop into convo with him you enjoy spending time with him. Its not too forward but your not revealing too much.
You could talk to your friend as well, especially if she already knows you like this guy. Tell her how you feel, its not very nice if she's playing up to this guy knowing full well you like him, that must be horrid!
If you dont feel confident, i wouldnt worry too much about chasing this guy,boys are shy creatures too, sometimes they expect us girls to make the first move!
Maybe just show him how much fun you are, like when your in the group dont put all your energy into him. Guys love the chase and your mate will be the one looking foolish in the end if all she is doing is being all over him. Independant girls who are happy in themselves and can laugh with others will stand out.
Then every now and again flash him a smile, look your best and keep him guessing.
And when you do bump into him be pleasant, smile ask him how he is doing. Get to know him more gradually in subtle ways and you will probably begin to find what you have in common, maybe more than what your mate and he has.
Just remember, never let a guy rule your head. Let them come to you. You want someone to like you for who you are.
And hopefully he will see the person you are. : ]
If we didnt have shadows we wouldnt be standing in the light..