How long do you tend to talk to a girl you approach during the day? Say I have somewhere to be but still want to # close, I've heard the advice to not eject yourself from the conversation but I need to be somewhere and I haven't built up the familiarity with her yet so shes comfortable to give me her number.

For instance I approached a girl today who afterwards said that she didn't know me well enough to hang out. I read that either that she isn't interested (which is fine), or I didn't talk to her enough/well enough to # close. I realised afterwards that a probably a good response to that is "well there's only one way to get to know me" or something along those lines.