We all use the mouse at some point on a computer but I prefer keyboard shortcuts so heres a few Firefox tips
If you have a lot of tabs open and close one by accident you can retrieve the tab by using this shortcut
On Windows press
On Mac press
And is if by magic your tab re-appears.
Spacebar = page down
Shift+Spacebar = page up
For the following ones if you use Windows substitute the Command key for the Ctrl key
Command + D = bookmark current page
Command + T = open new tab
Command + W = close current tab or window
Command + K = go to search box
Command + L = go to address bar
Theres loads more here
Keyboard shortcuts
Once you start to use the keyboard more for stuff in most applications things tend to get done a lot quicker!