Join clubs / sign up for recurring things* that interest you and keep showing up.

Odds are there are at least a handful of people like you in those groups … and odds are that the everyone else connections to people who could be your contacts.

Just by being there regularly, you become "one of the people in tech I know" of everyone else. And connections and opportunities start magically coming your way.

*It does help if these are the types of things that attract energetic, helpful, confident people.