That's it, I think. I think as long as enough of us actually do that, it'll make a difference. People seem to think that you need 50%+ of the users to "rebel" for there to be change, but the truth is that not all "users" are created equal. Developers, tech supporters (personal or professional), and "power users" matter more than typical users because it's our feedback, contributions, and demands that keep pushing these products forward. The "normies" will use whatever you put in front of them and they won't know or care that something could or should be different. If the nerds leave, the product will stagnate and other options will pick up steam.

unfortunately, there's not much else you get to do. With the exception of the anti-trust suits on google coming out with a decent outcome (which i wouldn't hold my breath for), there's little that individuals can do to push back against google's might.

If you're in a position of power in a corporation to dictate software usage, consider making firefox the default choice.