On your own? Not much. You can stop using certain products, save money, and so on. But that's mostly going to help make your individual existence a bit better/less bad. The CEO's aren't gonna give a flying fuck.

But our strength is in our numbers. Get organized. Maybe in a political party, maybe "just" in some sort of collective that helps in an area you care about. Help others in whatever capacity fits your abilities and your situation. And don't expect it to be a quick victory. That will only result in disappointment. As a wise man (?) once so succinctly put it: "Apes together strong."