Getting her number shouldn't be hard. If you've built sufficient attraction and rapport it will hardly matter how you ask, but having a plan never hurts, especially one that doesn't feel canned. I've used this so often now that it's become second nature (which is how it should be anyway).
--Oh, but let me first give credit where credit is due. This technique is derived from Suave Kino's Number Close, a man who has helped my game just as much as David DeAngelo or Tyler Durden. To read the original, click here, where by comparing the two you will notice which minor modifications have taken place.
When you reach a place in conversation where you want to number close, simply say,
"I'm sorry, your name is...?"
As if you'd forgotten or hadn't received it yet. When she responds, whip out your phone.
She will, and this is also a good time to give her a nickname.
"J-O-R-D-A-N. Jordan. Jordan Good Hair. That's your name."
Ready for it? Here's how you get her number:
Did I blow your mind? That's it. You say, "Number." It's not a question; it's a statement. That's why it's called the ASSUMPTIVE number close, because you already assume that she's going to give it to you. But Cody, what if she doesn't? She will. But--No, seriously. She will. I've never--NEVER--had it NOT work. It's the only way I n-close anymore.