Basically i find on campus there are girls that im "working" on, or thats on the edge of my social group that im interested in, but i meet them at time, ie in between lectures, when i, or they, don't have time for a long chat/ a close. What is the best thing to do here? Often they come up and talk to me, in a few cases because they are interested in me, and im a little lost on what to say in the 5-10 minutes ive got before the next lecture ect. I can have a conversation, i was wondering what the best way of maximizing your success with this girl later would be if you don't have time to talk but cant avoid a small conversation?

"Do you have a class right now? (no) Ugh... you're lucky, I do. Give me your number, I'll text you when I'm bored in there."

I'd send her maybe one text while in class about something funny that happened. She'll reply. Wait til later, then text back. That second text could be to invite her to go out that night, if you have something going on.

Those short chats don't matter unless you use them. You're looking for a number close, a meet up, then a real, sexual close. Make those 3 happen in order.

If you've already gotten the number, then during a short chat in person you could mention the party you're going to later and tell her to come.

If you will see these girls another time don't get her number at first. Just have a 5 minute chat and leave the chat at a very fun point and don't try to get her number. If you do this she will subconsciously think of you. She'll think "this guy is really fun" "does this guy like me" "if he does like why didn't he get my phone number" "if he's not into why did he talk to me" all these questions and thinking means she invested some time into you which means you have more value. Next time you see her she'll try to do anything to find out. Girls go beyond crazy about mysteries. So build tension and then get her number.

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"Experience is the teacher of all things"

This is true, but be very careful with this advice. If you're ever not sure, DON'T HESITATE. Do it!

There are a lot of girls that you won't see again, might as well make something real happen.