Girls of this sub, how would you want a guy to approach you exactly ?

I (M19) just walked past this girl who I made eye contact with in the store a couple of minutes ago. I said nothing because we were both with our family. I do regret not doing anything but it made me think about something. So it's easy for me to talk to new girls in my college class, but when it comes to outside, I don't know what to say.

It's quite simple to approach but what do you actually say once you do ? Like the reason you want to talk to her is obviously because of her looks at first so do you say that then go for small conversation leading to a number or what ?

I'm sure a lot of gents on here would benefit from this so please, if you'd like to share some knowledge, go ahead. Thanks!