It all depends on the situation. Small talk is all about your environment. You talk about things surrounding you or the situation that you're in at that moment in time. The problem with small talk is that it's boring. So once you intiate small talk you have to be able to transition into her personal life.
For instance, I travel a lot and while waiting on the plane, I always have a magazine or book to read. Most girls will have the same thing. In those situations, it helps to know a little bit about the magazine or book she's reading but not necessarily vital.
I take a look at what she's reading, if I've read it, then I'm golden, if I know the author, then I'm golden, if I've heard anything about the book then I'm golden. I'll ask what she thinks about the book so far. If I've read it, then I'll ask where she is in the book and tell her what I thought about a previous part. If it's a mag, (most times Cosmo or something girly) I'll ask her if she's taken the quiz in it yet? Ask her what they say about guys. Ask her what the quiz is about. (Get the idea?)
From here I guage her responses. Some people don't like to be bothered when they're reading. If you're interesting, they'll put the book down and from here is where you transition. Where are you headed? Is that where you're from? Who are you visiting? I then answer my own questions.
My goal in the end to # close. "You seem cool. What are the odds that we'll sit next to eachother? Probably slim huh? Well, we should get together once we get back. Give me your number and we can set something up."
Like I said... It all depends on the situation. If you're waiting on the train/bus, talk about your environment. "Starting to get a little cooler/warmer out here now huh?" Ever notice that the more miserable you are, the longer it takes the bus to get here?" If she's receptive, then transition. "What's your name? Where are you headed? You catch this bus here everyday?" Then answer your own questions.