Ask HN: How did you get your first users with zero audience?

Solo developer, no audience, no network, no community presence.I've shipped working products (open-source) but every distribution channel has a cold start problem. you need traction to get traction. Even posting about your work requires reputation you can only build by posting. For those who built something with no existing audience to launch to: what specifically worked to get your first real users? Less interested in theory, more in "I did X and it actually moved the needle."