You are new in a city. Suddenly you find a phone someone lost. You go through the contacts, see who last called and call back. The voice is relieved and asks you to hand the phone to a barkeeper. He gives you a free drink in return. That's it, you are on your own again.

How could you turn yourself from "the guy who found the phone" to "hey, who is that guy, I want to be friends with him"?

In other words, how do you turn yourself from a guy, nobody cares about and people are only nice to as long as he has their phone and that they ignore otherwise to a guy, people respect without him having to do much?