Just as mystery says, FTC FTC FTC.
"Hey, I've got to get to class but give me your opinion on ______" Then once they give it, "That reminds me, before I have to run I'll tell you about the time I saved a baby from falling off a cliff using only a toothpick and some gum... protector of loved ones... preselection ... leader of men... etc"
If you've reached the social hook point then you can throw in one last non verbal FTC such as the roll away (remember at this point the set wants you to stay hopefully) and follow that with another DHV, being sure to flip the attraction switches. If they are giving you that "who is this creepy guy vibe" I wouldn't push the number close, they'd just flake on you anyway.
After that you should be well into A2, hopefully A3. Throw another FTC and hand her your phone with a "I enjoyed speaking with you, let's get coffee tomorrow." Or whatever you like. Personally I never say, "Give me your number" I think it's best to have a plan of action and that way it's only logical that you have her number, how else are you going to tell her where to meet you tomorrow?
Good luck! Remember the 3 second rule and just approach approach approach. Throw up a field report afterwards would ya?
