I feel like this is an obvious answer, but everyone has things in common with everyone. Maybe you have a different job, different hobbies, or watch different TV shows, but those are not the only topics of conversation that exist. You live in the same city - talk about the neighborhood you live in and what you like about it. You grew up in different places - ask about that. The weather has been shit recently - complain about that together. Do they have pets? Do they have kids? Are they big cooks or love a certain type of food? What is there family like?

And you can talk about things that you don’t have in common too. You can still talk to someone who knows nothing about tech about your job or personal project. Talking about your job or code at a high enough level that anyone could understand is a great skill - hone it! And are you showing an interest in their job and hobbies that aren’t tech-related? Conversation is a two-way street and you can (and should) ask them about their jobs and try to be interested and listen even if what their passionate about isn’t what you are passionate about.

SO many people I know in the tech community talk about how hard it is talking with people outside of the tech community because those people aren’t into tech. Let me tell you me and my boyfriend are both software engineers and have a big interest in tech outside of work. We spend almost none of our time together talking about tech.