Okay, despite you being a pretty big douche generally here I'll give you one shot at a serious answer.
I mean, you ask what to do but it strikes me that you may not be able to pull it off yet. You're cruising around hoping for a fuckbuddy but you don't understand what a fuckbuddy even is it seems like.
Your fuckbuddy isn't your girlfriend. You don't pick them up like you're dating them. In my experience, you become friends with them first, then you both decide you want to fuck each other from time to time. It's pretty straightforward--you hang out a bit just like friends do, and then you end up alone together one night sipping martinis and you go, "Hey, you ever think about having a fuckbuddy?" If they're into it, they'll let you know.
And I think I can see why that's hard for you. Based on what you've said in this thread, you don't seem to respect women generally enough to actually become friends with one. You can get one in the sack and start up a relationship by playing the bf role, but you drop them when they start getting too serious.
You want a fuckbuddy, learn to be a buddy first. Hang out with some women you think are cool and sexy. Be their buddy. If they don't want to fuck you themselves, a lot of times if they like you, they'll try to hook you up--as long as you're clear about what you're looking for.
Now, if you don't even know where to find women to befriend, that's a whole different question. I would not bother with online dating/hook up sites, that's for damn sure.