Well, if she knows you like her, and she did smile lots of times at you, then it IS an IOI, so go for it, but not with a neg as opener.
I actually like this kinda cocky opener i usually use:
"Does it bother you if I make you company?" I dont even let her answer, I just interrupt her ask her something, so she answers.
Then you can offer her some gum, thats the neg you would be using, it's very sutile, but a neg anyways, and its really harmless. Then since you are with your friends, exchange a couple of words, say you have to go back to them, but it was nice to meet her. Say "Nice to meet you, kiss good-bye" pointing your cheek. I love that technique.
If she keeps looking at you, and/or smiling at you, the you go to her again, and then really take out the heavy artilery
