I get asked this question all the time: "Hey, Persuasion Guy..." (Actually, nobody calls me Persuasion Guy, though I wish they would). "What's the most surefire pickup line in a bar?"
Dude. (That's what I call guys who want pickup lines.) If a woman wants you to pick her up, just don't say anything that blows it. The woman will be judging you more than your lines. Which brings us to the theory of Ethos, your expressed character.
First, show that you care about the woman. A great pickup line? Ask her a question about herself. Compliment her shoes and ask where she got them. (Straight guys rarely compliment a woman's shoes, so at the least you'll surprise her.) This is eunoia, disinterested good will. It's the Caring part of Ethos.
Next, show you know what you're doing. Signal the bartender suavely. This is phronesis, the Craft part of Ethos.
Finally, show respect and good manners. That's arete, or virtue, the cause part. You're a genuinely good guy.
Yeah, some women aren't looking for a genuinely good guy. They're looking for an exciting, even dangerous guy. In which case, work harder on your Craft. And here you're on your own. I've been happily married for too long to look dangerous.
Here's a video Christina and I made. I cut out the part where she talks about what she thinks is the perfect line. Sorry. She already has Ryan Gosling as an imaginary boyfriend. - JAY