If you are interested in time management, I found GTD (getting things done) to be a pretty good book.
As far as flirting with girls goes...In my limited experience, most girls are usually flattered when you hit on them. In fact I flirted with a girl today, and I found out very quickly that she was dating someone. However, she still thanked me for hitting on her!
I've also noticed that it's possible to flirt with a girl, get her phone number, and then find out a couple of days later that she is dating someone. That's happened to me 3 times now! If you find that is becoming a problem, you might say something like this,
How does a cute girl like you stay single?
Also, I gotta give credit where credit is due. So the above came from Nick Notas.