Find a problem they are experiencing and introduce them to a solution they can self-host to fix it. Expand from there.
I began my self-hosting journey 7ish years ago with media piracy and a desire to watch/access my files wherever I was. Learned of Plex, then Emby, Reverse Proxies, Domains, SSL, and on and on…
Today I’m running 24+ docker containers and some miscellaneous stuff, across 3 systems; that’s always accessible via my domain/vpn.
Just this week, I setup Homepage to monitor my server and its various docker containers at a glance, including cpu/ram/network usage and a whole bunch of information pulled from their APIs (such as how many itemes are actively downloading via sonarr+sabnzbd, or how many queries were blocked by pihole today).
That in turn lead me too Glances, both as various widgets in Homepage as well as a stand alone tool.
Note: Homepage doesn’t come with authentication. You’ll have to handle that yourself via a reverse proxy or vpn. Glances has an optional login page you can enable, but I haven’t explored that. I access services like these by connecting to my network through OpenVPN.