Most Helpful Guy
Ask your friend about one thing that he's really passionate about and the just ask him "Hey, your sister told me you like (____), tell me more about it :)".
If you show interest in him, he'll show interest in you. You'll notice that right after he finishes talking about that topic, he asks you something about yourself.
Try to look him in the eyes when he's talking, it's really powerful when trying to make someone be interested in you, and like you.
Most Helpful Girl
I think if you smile , it will put him at ease and help him see you easy to approach.
Watch your body language. Keep it open and lively. You don't want to look closed off.
Try to keep him in every conversation because you might tend to talk to your friend more so you don't get awkward.