First step definitely would be to identify specifically what you'd like to improve. To say 'tech skills' is to cast a wide net. If you want to learn all sorts of things that's fine, but to get started with that and identify resources you have to be at least temporarily specific.
Are you thinking along the lines of system administration? Networking? Programming? Hardware setup/troubleshooting?
Generally I read HackerNews and Lemmy communities like this one. Once in a while interesting projects will get highlighted.
But for the most part, once I identify a need, I'll look through alternativeto.net and see what the popular open source options are.