Educating oneself in business matters

Greetings, I’ve read many investing books that say stock investing should be approached as becoming an owner of a business. The idea is that the better you understand the business, the better investor you become. The only industry I understand well is the one I work in—tech. Because of that, I tend to hesitate when looking at industries outside of technology and, to a lesser extent, consumer cyclical stocks. If I had been investing in the early 2010s, I would likely have recognised many of the changes coming to the tech industry, because I was seeing them firsthand in my daily work. However, I don’t really understand other industries such as resources, pharmaceuticals, insurance, and so on. So how does one educate oneself about industries they are unfamiliar with? Do you simply avoid those industries, or do you rely mainly on financial reports to identify undervalued stocks?