If you're not sure if you want to go on a date with a girl or not, it's fantastic how useful, "What's your schedule like?" works.

The girl will invariably respond that she is busy that week. It doesn't matter if she is busy, it doesn't matter if she likes you, it doesn't matter if she wants to meet up THAT DAY. I had a girl chasing me down on Saturday, used that line on her on Sunday, and she was busy for the week. And then trying to meet up with me on Monday.

As long as you keep her sufficiently interested during this period (an unrelated skill) you can buy yourself quite a bit of time.

The main trick here is to either play it straight - i.e. treat it like she is legitimately busy if you decide you want to not hang out with her for a few days, or completely ignore it (after building her interest strongly right before you ask) if you decide you actually do want to hang out with her.

You still have to keep up contact (I'd say at least a text every two days, with responses back), and you can also tease her about whether she's worth the wait. If you do it right, SHE will be dying to hang out with you and hate herself for imposing a time limit.