I'm pretty strait forward. If she has a nice smile I think "hey, that's a nice smile." I told you, lol. If I'm attracted to the girl I'll try to find something to talk about, maybe compliment her, depends on where I am and what's happening. But I don't always think the girl is attracted back, sometimes that can take a while. I think up a ton of reasons why the girl smiles, like, maybe I smiled first, lol. However, the more you compete with my flirting, then I might start to think there's attraction, something like that.
I think she has a little interest in me, probably enough so that she'd be willing to have a conversation with me for about 30 seconds. From those 30 seconds, either it'd end there or go further. Or, it'd never begin if neither of us did anything besides smile.