There are a growing set of decentralized technologies that are available and worth checking out. They provide a glimpse into a better strategy and the more people use them, and contribute to them, the better they will get. For almost every service that a tech giant provides, there is a community building a decentralized version, and I look forward to the day when the next killer tool or service that will make your life better will come from that community. That day is coming, I think.
But I do think we need to clear more space for that world, and some of it will take legal and policy changes, not just individual choices by users and developers. We need to stop the blocking of interoperability by laws like the CFAA, DMCA and those click-wraps you don't read that prevent reverse engineering and other steps we need to make new tools that let you interact with old ones. And we may need some affirmative requirements that companies allow and even foster interoperability.
In the meantime, there are some things that regular folks can do. EFF doesn't endorse any specific tools or services but folks who are interested should check out privacy protecting tools like Signal and Tor, tracker blockers like EFF's Privacy Badger and privacy protecting browsers and services like those offered by Firefox and DuckDuckGo. There are others, of course.  And do use your privacy settings even in services like Google and Facebook. They aren't great but they also do send a signal that you care. I often debate company shills who maintain that people just don't care about privacy and security and when I ask how many people adjusted the privacy settings, it points to the fact that people do care, we just need better options.