https://www.privacytools.io/

I urge everyone to take a look at this website (as a starting point).

Use a vpn that has no logs.

Use an adblocker like ublock origin.Read the ublock origin documentation or watch TheHatedOne ublock origin video on Youtube to better understand how to use it to it's maximum potention. https://github.com/gorhill/uBlock

Watch Youtube videos without all the spyware. Invidious is an open source front end for Youtube. https://github.com/iv-org/invidious

You can use rss for youtube channels. With a combination of mpv player + youtube-dl you probably wont ever have to visit the Youtube site unless you want to read comments.

Use open source browsers like firefox or brave.Also make sure to go the Firefox/Brave settings to make it more privacy friendly. Firefox out of the box has very bad privacy. If you are planning on using on using firefox, make sure to harden it (look at the link i gave).

Abandon Microsoft and Apple. Embrace Linux.

And this is just the beginning.

Install a custom rom (read about LineageOS with or without MicroG) or root your phone. Whether or not you do those, you should still do the following -

Use privacy friendly open source apps on your phone from F-Droid. https://f-droid.org/

Some examples - Newpipe instead of Youtube. Y

It is better to use the browser instead of relying on apps though. Use Fennec browser (Firefox fork from F-Droid) or Bromite (you need to add the repository first), Firefox from the Google Play Store has telemetry.

Deny permissions to apps that you think is unnecessary. Or remove the app. Whether you are on pc or android, wipe out metadata from files/pictures before sharing it online or with anyone.

Don't believe the nonsense that there's nothing you can do to stop big tech spying on you. You can at least minimize the spying.