Because it is so much more efficient to keep your hands on the computer keyboard (and skip any extraneous mouse usage), any time you spend memorizing a few keyboard shortcuts will end up saving you a lot of time. This About.com page has a nice collection of Firefox shortcuts. For example, use ALT-D to jump to the address bar and highlight the current contents. Simply start typing to overwrite the existing location.
Cite This Page
Feldman, Barbara. "Firefox Keyboard Shortcuts." Surfnetkids. Feldman Publishing. 10 Sep. 2008. Web. 20 Nov. 2014. <http://www.surfnetkids.com/tech/325/firefox-keyboard-shortcuts/ >.