Often, when I want to approach and I can't think of anything to say, I just straight up walk to the person and ask for their name. As long as you do it in a friendly manner, you will get a friendly response or answer.

Just this morning, I went to a food joint where there was a really cute cashier who always seemed to be frowning. I've never seen her in a good mood at all, but I got to thinking maybe she's just guarded. So as I was paying for my meal before leaving, I just asked her what her name was.

She was counting my change at that point so she was looking down, but then she did something that she probably could no longer stop herself from doing at that point: she flashed a beautiful smile. It's like how you stop and smile to yourself whenever you witness or experience something wonderful. That's the kind of smile that she did earlier, and that was just because I asked for her name.

So she told me her name. What I did afterwards was simply smile back, take my change, and say thank you then left. The interaction didn't last more than 2 minutes, but I could tell that I've already made her day.