ok im going to be brutally honest, you need to get over ur shyness, and it sounds scary but, once u go out there and literally FORCE yourself to go and talk to girls, youl get more confidence.
i can tell already, your probobly scared of rejection? yes, i thought so. you need to remember though, if you go and talk to a girl about anything (nothign sexual or shel think your trying to pick her up) she'll be flattered if anything, so if you adopt this attitude, it'll make the whole process alot more easier.
why not just go up to this girl and say something subtle like " hey i think ive seen you before, if i remmeber rightly your a great dancer, wats your name?"
somehting as simple like that will kick start you, and if u try and have a conversation with as many girls as u can, ur confidence will grow.
i see alot of people say you need to get more confident, and that doesnt really help because you need to know HOW to get more confident. i can help, and if you want any tips just pm me
joe