+1
Straight-forward pick up lines don't work. Girls have heard them all, probably numerous times already and all it does is make them think: loser ^^
I once saw a guy approach a friend of mine, fish out the ice cubes from his glass, drop them on the floor followed by the words: now that the ice is broken, why don't we get to know each other a little better. She was laughing alright, but only because the whole act was just pathetic.
In my experience, hooking up with some random girl at a bar / club is best done indirectly and it depends hugely on the mood that you're in.
indirect openers I have used (girlfriend, can't do this anymore ^^) that are somewhat successful:
Hey, there is a guy over there that is just perfect for you!
She's always going to refuse, then you can talk to her about how you're actually a matchmaker, dating, relationships, what she likes in guys,...
You guys! Get ready cause I'm gonna chat you up!!
You're basically announcing your eventual intention, but add stuff like "i don't know how many times guys have already tried to get you in the sack, but seriously, this is going to be the best ever!". Then you just tell her some lame pick up line like "Is God missing an angel?? Because you're here!" If you say this being very unconfident and looking for approval, then switch to being a fun guy who just mocks this sort of thing, they should like you a lot and you can chat about guys approaching them, what was the best/worst etc.
Do I look gay?
This is the best one imo. After they give you the wtf-look, you should tell her that some guy just tried to pick you up. I guerantee you that the girl(s) will laugh. Then you can just make some assumptions, funny guesss about her to start a proper conversation.
That's my 2 cents anyway.