Learn how to configure Firefox, so that you can prefix your URL bar search with a keyword, in order to search a different search engine, such as Duckduckgo, or this blog.
Learn how to configure Firefox to always show the full URL, rather than hiding things like "http://".
Use the power of profiles in Firefox to make managing your multiple identities much easier.
Install and run Firefox nightly in order to see the benefits that will eventually make it into the released version.
Discover a workaround to ensure opening up Firefox is always almost instant.