In Mozilla Firefox, you can use the combination of different keyboard keys to accomplish your routine task. With shortcut keys, you can speed up your surfing without lifting your hands from the keys; otherwise require a conventional mouse to select menus and buttons options. Basically keyboard shortcuts keys help you to save time and you can perform any tasks without leaving the keyboard keys. 
Useful Mozilla Firefox shortcuts keys

Shortcut keys                        Action 
CTRL+A                     Selects the all items on active page
CTRL+B                     Display the "Organize Bookmarks" dialog box
CTRL+D                     Include the active page to your Bookmarks list
CTRL+F                     Display the "Find" dialog box to search text
CTRL+I                      Display the Bookmarks pane
CTRL+H                     Display the History sidebar of Mozilla Firefox
CTRL+N                     Use to open new Mozilla Firefox page
CTRL+P                     Use to print the active web page
CTRL+R                     Use to reload the active web page
CTRL+T                     Display a new Tab in active Firefox window
CTRL+U                     View the source code of active web page
CTRL+W                    Closes the active Mozilla Firefox window
CTRL++                     Use to increase the font size of active page
CTRL+ -                    Use to decrease the font size of active page
CTRL+Tab                  Move to next Tab in Mozilla Firefox
ALT+Home                 Use to open the home page of internet explorer
ALT+Left Arrow           Go to previous page of active page
ALT+Right Arrow          Go to next page of active page
ALT+B                       Go to Mozilla Firefox Favorites Menu
ALT+D                       Go to address bar of current Firefox page
ALT+E                       Go to Mozilla Firefox Edit Menu
ALT+F                       Go to Mozilla Firefox File Menu
ALT+S                       Go to Mozilla Firefox History Menu
ALT+T                       Go to Mozilla Firefox Tools Menu
ALT+V                       Go to Mozilla Firefox View Menu 
Tab                           Move forward between all items on active web page 
F5                             Refresh the active web page
F7                             F7 activate the cursor to move with keyboard 



CTRL+SHIFT+DEL           Use to clear all Private Data history 
CTRL+SHIFT+D                Use to Bookmarks all Firefox Tabs 
F11                                       Press F11 key to view any webpage in full-screen view and then again press for normal view.
 
Press Ctrl+Enter           Windows will automatically add both "www" and ".com".