There are many resources available for that, and also schools if you want to go professional. I was doing web programming before, but I started working on standalone games 10 years ago with resources like Game From Scratch (https://www.youtube.com/c/gamefromscratch/) and later, Brackeys (https://www.youtube.com/c/Brackeys/). I’m on the code side of things but you can find your own field(s) of speciality. But more importantly, stay with the community: in the case of PICO-8, looking at other devs’ work and talking with them about how they do it is very instructional.