Judging by your post, you dont have much experience, opener doesnt matter as much as the conversation.
http://www.youtube.com/watch?v=5OsnTnWEKLk
Honestly, practice is the #1 things to do. Open poorly but calibrate with the conversation, alot of the practice will be on flirting, teasing and positive energy.
Cause is not something that comes naturally.
So instead of ask for an opener, just memorize one that you use most of the time, when you meet new people.
Mine is " Oh hey, I was over there with my friend and I notice your style and I find it interesting. My friends are too shy to come over. So I decide to break the glace. So who are you?"
Make it really simple cause the main part of the whole pickup is conversation and vibe. Approaching someone doesnt mean you are fucking them, simply because you are being social and outgoing.