If he already likes you back, then you don't need to worry about it. But if not yet, then always be very happy, cheerful, and fun. Have a big smile on your face and just go have fun with your friends. Hope I helped:))
Some of the ways you can employ while flirting with your crush may include being touchy through hugs, holding of shoulders and having a warm smile. You need to be very confident and be conscious of your appearance and personality. Check out http://teenadvice.about.com/od/datinglove/tp/how_to_flirt.htm for more information.