Extensions: uBlock, Privacy Badger, Decentraleyes, DDG Privacy Essentials, HTTPS Everywhere, and most importantly Containers
I try to keep as many sites as possible into relevant containers. Facebook and Google get their own containers just for them (there are additional addons which will handle this for you as getting all of Google siloed off is cumbersome otherwise).
I also make use of the built in tracker blocking, blocking all third party cookie use entirely. There's also an option to resist fingerprinting that I enable, which does a ton of things [1]
For blocking I'm using uMatrix, plus uBlock Origin and Ghostery. There's a lot of overlap and it might not be the most efficient, but there are reasons. This is fine for sites that I'm on regularly, but is annoying for one-offs. I actually flip to Chrome with only uBlock Origin for some purchases and for some specific websites that work better there (like GMail), though I could probably use the Firefox beta channel builds as a non-locked-down browser for that.
uMatrix generally blocks third-party items, though it defaults to allowing CSS and images from anywhere and I haven't changed that. uBlock Origin provides list-based blocking instead and is a failover if I give up and temporarily turn off uMatrix for a site. Ghostery is useful for a quick reference of why various things are blocked in terms of website categories (trackers, discussion, ads, etc.).
I'm also using DeCentralEyes, which provides locally-injected versions of a lot of CDN-based resources.
