You see a girl you're attracted to and want to ask out. What I do is I get near them and try to make eye contact. When I do, I simply follow up with a "You have beautiful eyes."
In my experience, they usually smile and say thank you. From there, it's easy to follow up with "I'm "Krebs". What's your name?" Once I get the name I make something up like that I have to go but that I'd like to take them out to dinner.
Huge success rate. I almost feel like I've inputted some sort of cheat code in life with this method.