Creating a design system / component library as a solo dev in a small agency

Hey guys, I need some resources / advice on creating a component library for our marketing website builds we do. Right now, I think I have it organized OK, but definitely lacking maturity / polish (which I know will largely come with time). I think with the right direction I can get there faster and polish some things up.

And I know this is vague; I could show you an example of how we're implementing some things but I don't think it matters -- just looking for some general advice on what things to do or look out for.

Maybe some advice on how to plan / what to start with first? Thank you!