Instead of introducing yourself to other girls, just start talking to them.
If you aren't sure you know them or they know you, it will be apparent
in the first 30 seconds of conversation. If they don't know you, they
will most likey introduce themselves and then you can do the same.
I always pride myself on going up to people and saying hello and
introducing myself. This backfires sometimes and on Saturday
it backfired on me twice.
Me: "Hi, I'm een."
Her: "Uh, yeah, we met at the bar a few years ago." Followed by eye roll.
Me: "Right! Nice to see you again."
Her: Weird smile.
Ok, sorry if I didn't remember your name or if perhaps I was intoxicated
and forget that we met. Stop judging me. I thought I was being polite by
introducing myself. I try to avoid the whisper to the friend "Whatsernameagain?"
by greeting people and saying my name again. Whatever.
Sometimes I wish I was a guy when they congratulate you for being
drunk and not remembering someone. He would probably even buy you a drink.