You made a few mistakes here. I'm going to have to assume for the first one, but my guess is you didn't spend more than about 5 minutes talking to her. If that's the case, you didn't build attraction or rapport, and she's probably going to flake on you, if she even answers the phone. See, the first thing a guy judges a woman for is her appearance. Personality makes a play there too, but for most guys it's not nearly as important. So we see an attractive woman, we know we'd be interested in her.
For a woman, however, that's reversed. Personality is much more important, with looks not so much so. I know people here will argue with me about this, but that's the way I percieve it.
So when you meet her for a short time, get her number, and leave, you haven't really done anything to display your personality. Why should she choose you to spend her time and energy on? She doesn't know you from the next guy. Like I said, probable flake if she even answers the phone.
The second mistake is framing things as a typical date. A date has the potential to be a boring, awkward event, where two people who barely know each other are stuck with each other for a specific length of time. I wouldn't bring this up, except that you mentioned getting dinner. Baaaad idea, even as far as standard dates go.
Instead, reframe the situation. It's far more attractive to be a man with lots of things going on for himself, so tell her you're doing something, and that she can tag along if she wants. "...but I don't really know you that well, so for now you're on probation. If you start acting like a dork, I'm gonna have to kick you out of the he-man woman-haters club." (reference to The Little Rascals)
Hmm. The text doesn't really convey what I meant by that, but trust me, if you can put a C+F spin on those sentences, it conveys exactly the mindset you should have about this entire thing. One of "I don't know her, I don't know if she's qualified to hang out with us, and I'm gonna tease her mercilessly. Or at least for as long as she's having fun with it."
Third problem: Phone game. I'm still working on this myself, but if you wait a long time to call, it will not build attraction for you. If she's even reasonably attractive, she's probably got other guys giving her attention and validation, so she's not gonna stress too terribly much if some guy she barely knows didn't call her.
It would be like being at a chinese restaurant, and a friend of your says he's gonna go out and pick up some McDonalds food too. Except, he's too lazy to go out and actually get it, so you all just eat egg rolls and chow mein noodles or something. The point is, you're not going to be too concerned about a vague potential that never actually materialized when you have other options in front of you. Same thing goes for women. To them, you are the McDonalds food, unless you can prove differently.
Get good at opening, then building attraction and building rapport (in that order). Once you do that, get enough numbers to let you work on your phone game without worrying about the reaction from any one number. Call them up whenever you feel like, but just so you know, the numbers will usually stale within a week, so work them hard.
Oh, and call this one practice and don't expect anything to happen because of it. Otherwise you're setting yourself up for disappointment and possible oneitis.
