I'm walking or standing in line. I spot a chick looking at me. We lock eyes. 1 or 2 seconds pass. There are 20 feet between us. At that point, what should I do until talking to her? Please describe me like I'm a retard.

Should I stare her while walking towards her, should I do an eyebrows flash and a tiny smile, should I yell hi (there is distance), should I break eye contact mid way?

I look somewhat aggressive if it matters. I don't want to creep them off because it is a small town. So I feel like I gotta smile a little bit.