Eph said:
Don't comment, don't like. Women get enough attention, period (a negative reaction is still attention btw), so don't be another beta giving it to her. And if you even try to say anything negative, whether you're joking or not, you'll get attacked by a swarm of white knights.
So, it's best not to say anything. Do your talking offline. Or let your pictures speak for you. She'll notice if you've got 20 people liking your shirtless selfie.
I will both agree, and at the same time disagree, on your answer.
It depends on your persona and the way you are, IF you are stalking her every night, always online on Facebook and so forth, then follow the above advice, if however you have multiple plates, less active on Facebook, and play the role of the "mysterious guy with lots if secrets" this is how you do:
When she puts up a new picture, NEVER like it immediately, and never like the one she just put up. Let the "swarm" of likes cool down, and wait a couple of hours, the go back in either her profile photos/"random album", and like an older picture. This will defiantly make her notice you, and make her wonder why you liked her old picture, and not her own.
Trust me on this one, it may seem dumb, but I get a reaction 9/10 times. Either she like back one iof my pictures (then you know it's on for sure), or else she writes me on the chat, just some random message.
However!! This will only work as long as Facebook isn't your fulltime hobby, as long as you don't spam these girls every day, as long as you aren't posting Facebook updates and so forth - AS LONG AS YOU DO, what you should be doing, this WILL work.
If you are a full time Facebook stalker, then stick to Eph's advice, which is very good, BUT a passive move.
Regards,