Well man maybe give her a compliment and call her stunning.
There was good advice about talking about books because its her job and she could talk alot about them. But then again this is kinda indecisive and not decisive action.
You see you looked at her and didnt talked. She might already started to think that you are shy guy or something. "What is his probelem lol?"
You can aswell go to her and say "Hey you look amazing. Obiously Im not here to talk about books I just wanted to talk with you say how beautiful you are."
Something like that. That compliments shows great amount of confidence and being straight to the point shows confidence aswell.
I mean you have to decide what you want from this girl. Do you just want talk nicely to her for few minutes and be like a friendly guy. Or do you actually want to make a move and ask phone number and ask her out for a coffee.
Check out my guide - its about approaching girls.
loveforum.net/the-relationship-news-and-articles/85674-guide-interacting-girls.html
Doubt kills more dreams than failure ever will