My own personal tips as a guy in the field for a long time:
1. If you're worried about being spied on, the first order of business is to stop using a cell phone. What they know about your travel/shopping/life habits is creepy, even without any data from your apps. Even without real or fictional ways they might be using your camera and microphone. They always know to a few feet exactly where you are.
2. Delete facebook & gmail, use protonmail.
3. Never tie logins to one site, e.g. an RSS news service, to accounts of another, such as gmail. (i.e. "log in with gmail" is evil).
4. Use a VPN. If you're not using a VPN, at least make sure your DNS server isn't google's, but your ISP will still know what you're visiting unless you use a VPN.
5. Alexa is a great tool if you need to help a blind person. I would never have one in my home otherwise.
6. Microsoft isn't innocent. They are collecting data and trying to rope your every activity and system configuration into their ID services. Use open source where possible, and when configuring a new windows machine, keep it off the network until it's "configured" to avoid getting roped into things like Microsoft LIVE, etc. Consider a Linux based computer.
7. Not sure what to say about Apple, never used 'em, never will. Margins are just too high.
8. Every picture you post can and will become machine learning (ML) fodder, and unless you're paying for a private service, the terms of service let the service provider use the photo as they see fit, i.e. that picture of you and your dog could become advertising.
9. Somewhere someone is running ML that could easily identify me from this post by comparing it with other things I have written.
10. TBN knows a lot about us, and no doubt someone is working hard trying to monetize that. I don't have a solution for that.
Have a nice, insecure day!