Guys
“Hey”
Girls
“Hey”
You don’t have to start off that way, that’s only the way I do. There’s no set way to do it, no rules.
I’ve found guys are more likely to respond to that (friendlier? less judgmental? interested?) than girls. If a girl isn’t interested she will ignore you and not say anything at all.
After “Hey,”
ask them about their day, interests, hobbies, etc
talk to them like you would with any other you met for the first time.
You can hit on them, say inappropriate things, or be an ass all you want but it won’t get you anywhere. You won’t even get them to meet you for coffee or a drink.