why is ur nick XiaoGalGal1990?
(lol)
Assuming you're a guy (it's actually ok if you're female
also)
Try striking up a conversation with her and hopefully get her
number. If you've missed the opportunity, get her number from
alternative sources (like her parents, common relatives, your
parents etc.)
Start off by being friends, express your interest in her, but
don't go too quickly because she may be scared off if you're too
direct. 船到桥头自然直...