Here is the situation: I have met this girl in order to give lend her a book at university (she asked for that on fb). Once I met her I found her very very cute but we were both in a hurry and didn't had the chance to talk a lot. She smiled a lot and I think she is single (tried to "stalk her" on fb). I am going to see her tomorrow so that she can give me back my book. Now: do I ask her out tomorrow even if we barely talked or do I try to talk to her a few times on fb or at some classes in order to build more rapport and find the right occasion to ask her out?

But mine is also a more general question: do you tend to ask immediatly to go to out to eat something (/goint to the cafeteria/buying an ice-cream, etc) or do you wait to see her again and talk to her to build more rapport?