Angua nailed it in post 18.
Personally whenever anyone has used a chat up line on me I've been INSTANTLY turned off.Chat up lines show you are trying too hard and are desperate for
anyone.
Better to talk normally and discuss the venue,the weather,the music,admire her taste in clothes, or the occasion at which you have met.It's also nice if you can just introduce yourself or get someone to introduce you.Be honest and say that the person caught your eye and you thought they looked like someone you could be friends with..
It just takes a little courage to step over that space with embarrassment stamped on it.However being normal will take you further once you have made that first step.The girl is probably as nervous as you.If she isn't and is one of those chumps that know they are God's gift and you are a dog turd beneath her feet well you are better off if she gives you the brush off 'cos she's not worth knowing.
Remember! Chat up lines are for creeps.
Good luck!