Consiglio del giorno che ti può essere utile:
I have to go through the same guarded gate every morning for work, I often work with customers on a repeat basis, and I shop at the same grocery store pretty frequently. I started trying to be more friendly and outgoing a few years ago, starting with people I saw a lot. Since then, I've built some great rapports, and even friendships, with these people. It's made it so pretty much wherever I go, I have a friend or someone knows someone I know. On top of just being nice, this has come in handy many times. There has been times in which I've needed something from someone, and their tone has changed completely after I mentioned that I knew so-and-so. Also, when I go into coffee shops in which I'm buddies with the baristas, I often get free drinks/stuff they were going to throw out.
The “I know a guy” thing is really as simple as that.