I researched and installed uMatrix immediately, but (due respect to the creator) the application is so hard to use and broke several web pages. I also installed WebRTC Leak Prevent Tool that helped a little.

Disable all these preferences from firefox! https://github.com/TheCreeper/PrivacyFox

Add: https://github.com/straytachyon/dnsmasq_ad_block_script

Add2: You can even block select corp: https://github.com/jmdugan/blocklists

Add3: https://news.ycombinator.com/item?id=11791052

Citation needed.