I recommend poking her. Facebook game is a lot like text game, so a poke is kind of a playful "Hey

" If she doesn't poke you back, then whatever, but it's literally a one click maneuver--kind of like the new way of saying happy birthday to people without having to leave your home screen. With it being that easy to initiate and return a poke, it puts you in good position to make any stupid semi-sexual neg/joke like "you must poke all the guys" etc... This is just one easy way of getting the ball rolling. Also, since Facebook has now combined chat with messaging you don't have to catch her online, you can just drop her a neg here and there after you've started joking with her. As far as you having known her before check out this link
http://www.youtube.com/watch?v=xiVDL_mN ... ure=relmfu
Just skip to 38:50, the guy goes over embodying an attractive image. I wouldn't recommend copying him verbatim, but I would recommend applying it to getting girls/this girl you're already acquainted with. Good luck.