I'd read books that contain case studies of systemic phenomena. Like books on evolution (I'd recommend those by Dawkins and Dennett) or economics (even somethin

I'd read books that contain case studies of systemic phenomena. Like books on evolution (I'd recommend those by Dawkins and Dennett) or economics (even something like the Planet Money podcast). Reading about specific cases is good for honing your intuitions about systems, which is important for being able to think in systemic terms. I don't know your background but I also think learning programming is valuable.