They key of getting numbers is grabbing them as soon as humanly possble. In your first approach, establish rapport, and develop a mutual interest. Then go for the number-close or set a date. If she's interested in you at all, you'll get a positive response. If she doesn't, then she's just a friend and you don't have to waste the energy to keep working on her.
I've found a wonderful tactic that I use all the time on girls to grab numbers.
After you've created interest, fake a time restraint. Examples:
-"Dammit, my friends are waiting for me."
-"I really have to get back to my buddies"
Then set a venue but say that you're going with your friends. Examples:
-"Hey, Me and my buds are gonna head down to the theater this saturday."
-"Afterschool, I'm going to drive down to *restaurant* to go eat with some friends of mine."
Then tell her that she is welcome to come.
-"You should come with."
-"Let's go together."
Then interject with a number proposal.
-"But we need to make the plans, so gimme your number."
-"Let me have your number, and I'll give you the info."
Then set a time and location to meet:
-"Just meet me back here afterschool. I'll be a bit late, so just wait here."
Disengage the conversation
-"Now, get to class, you!"
-"Now get outta here, I have things to do."
-or- use your original time restraint
-"I gotta get back to my friends, cya."
It's a rathe simple way of grabbing a number. This whole interaction shouldn't take more than 45 seconds or so. I just spread it out to show you guys how each part works. You can tell immediately if she is interested or not, by her choice to give you the number or not.
-Damian
