First of all, try to find out what he likes and what he is passionate about. If he is into sports or music, find an intriguing but interesting topic of conversation as a reason to approach him. Show your knowledge of the topic he is most interested in and you'll become a desired company. Also try to appeal to his personality. Talk to his friends or people, who has known him a long time and ask what his tastes for girls are. Be yourself but also act a bit in his-girl style. Show the unique side of your personality and emphasize the one that will be attractive for him and allow you to hook him up on that.

Good luck!