Ever look at a girl and have her smile at you?
It's one of the oldest approach invitations in the book, and also one of the clearest.
Whether she smiles at you first or you smile at her, then she smiles, if she holds eye contact with you while smiling at you, you've got a ringer.
I've used this approach invitation to identify girls it'll be real easy to meet for years.
I've even had girls I held eye contact with and shared smiles with do the opening themselves. There's something about that mutual locked eyes, shared smiling signal that emboldens even women to make an approach.
I've used this to prompt a fair few girls to approach me themselves in social venues. I would've approached them myself later had they not made a move, but sometimes once she's had that smile and locked eye contact from you she's going to dive right in.
One of the few times I've been street-stopped it was by a really good-looking 20-something girl in a tan business suit on my way to the subway midday on a weekday after we locked eyes and shared smiles. She was so forward it took me aback; I doubt she'd have had the confidence without that prolonged smile and eye lock.
A lot of guys overthink this invitation.
"She's just being friendly," they think.
"Maybe she's just having a good day."
"She could be smiling at someone else."
Yet the vast majority of the time a woman is holding eye contact with you and smiling at you somewhere, it is not because she's just having that splendid of a day, but instead that she likes you and would like to meet.