While I don't think facebook is the best place to pickup I'll agree it's one of the best as far as looks and searching goes.
I started using this approach about 4 years ago and it actually landed me a lot more than I expected (I actually just broke up with a girl I met on fb a couple months ago).
This approach is simple as hell and has gotten me consistent numbers/lays, actually it was so successful I wrote a book around it (Push, Poke, Pull)
Ok, here is Push, Poke Pull
1. Find an attractive girl on facebook
2. Add her- if she doesn't accept I would stop right there just move on
3. If she accepts, view her profile and POKE her
4. If she Pokes you back it's on
5. Simply message her "Did you just poke me?? :-P"
6. She will most liking reply saying "you poked me first"
7 Message her back and say "yea...ok haha listen, I've gotta run give me your # and I'll just txt you." (you get the basics you just need a constraint that you're going to sign off and that texting is the easiest way to continue the conversation)
That is it! Go out and try it and if it works send me a thank you (or buy my book haha)