There's been a lot of talk at Pagliacci and Andster's blog about using magic to pick up girls. While I've never gone out with strictly this purpose in mind, I frequently use magic to flirt with attractive girls or let them know what I think about them. Although I haven't thought about magic and girls as deeply as Pagliacci and Andster have, I thought I'd share my advice/experience on the subject.
Never make a 'cold' approach with tricks. I always chat for a few minutes before I even mention the fact that I do magic. In my experience, the best tricks involve
a) visual magic with cards
My favorite trick to perform for girls would definitely be Paul Harris' Backlash. It shows off your skill, it's an easy and 'intimate' effect, and it leaves the girl with a fascinating object to remember you by.
For me, the easiest type of magic to pick up girls with is what Pagliacci called "Magic others have initiated, magic that makes me the center of attention, visual magic, up the ante for future behavior." Often, when I'm performing at a bar or a party, I'll get a large group going pretty quickly, and a few attractive girls will work their way in. Once I notice them, I get them involved and start to flirt a little bit. I guess this would be the best situation to start practicing picking up girls with magic. Or 'magical seduction.' Or whatever you want to call it.
In my experience, magic works best as a way to flirt with a girl you're interested in, and show her how interesting/funny/mysterious you are. But don't use the magic to draw attention to yourself and then fumble with the actual 'pick-up.' A killer handling of the sponge balls will get you nowhere if you do nothing else to distinguish yourself from the other losers that approach girls. The magic is important as a means to an end, but every other part of your interaction with the girl is just as critical. This guy is an excellent source on that sort of thing.
That being said, here's my contribution to the list of effects that can be used to pick-up women...
This trick works best as a closer, after you've picked your 'target' and have been flirting with her for your entire performance. You need a duplicate Ace of Hearts. Draw an "I" above the heart, and a "U" below. You can also draw an arrow through the heart if you like.
Set this duplicate on top of a regular Ace of Hearts, and put the two cards on top of the deck. Do a double lift and then an Erdnase change. Reap the rewards, you sly devil, you.
If you like, you can set the Ace and the duplicate up to do a twirl, snap, or shapeshifter change. It's all personal preference. Just don't screw up or you'll look like an idiot.
The trick was taught to me by a guy named Dominic at Tannen's Magic Camp. I can't remember his last name. If this trick works and you run into him, throw a few hundred dollar bills at his feet. I know I'm indebted.