MozillaWiki and
mozillaZine are usually good places to start for anything Firefox related. Unfortunately some of the pages can be quite out dated, particularly on mozillaZine. Relevant pages from these sites would be
https://wiki.mozilla.org/Privacy/Privacy_Task_Force/firefox_about_config_privacy_tweeks and
http://kb.mozillazine.org/Firefox_:_FAQs_:_About:config_Entries.
There are plenty of other sources out there that will discuss the same things that I have, and Google or Duckduckgo are your friends for this. Here are a couple of other good sites that may be of some help:
https://wiki.archlinux.org/index.php/Firefox/Privacy and
https://gist.github.com/0XDE57/fbd302cef7693e62c769.
There are plenty of other about:config tweaks you can make to improve your privacy which you can read about on the sites I've linked, but many of them (such as disabling all cookies, which will break any site you need to log in to, or disabling phishing and malware prevention because it sends every URL you visit to Google to be checked) don't appeal to the average user, which is why I didn't mention them in my last post.
