in a way, it's stupidly easy to spot single girls when you walk around a city on weekend nights. if they're not with anyone, there's a good chance they're single.
i went out with a Swedish guy i ran into last night and we walked around. a guy we walked along with for a little saw a girl waking toward us and stopped to chat her up. that's how uncomplicated it was for him. "hey, what are you doing out alone?" kind of thing.
sometimes, as a nerd, you do tend to overthink things a little...