A great way to improve your productivity on the computer is to memorize a few of the many Key Commands available to you.

Here is a link to the common key commands on the windows system:

http://support.microsoft.com/kb/126449

This is a similar page for Mac OSX:

http://support.apple.com/kb/HT1343

Here is a list for Ubuntu Linux:

http://ubuntuforums.org/showthread.php?t=50794

Usually, the apple key on Macs will do the same as the Control key on Windows or Linux based computers.

The most commonly used and useful ones are:

control c copy

control x cut

control v paste

control a select all

control z undo the last item (sometimes this works on more than just the last item)

control s save

control w closes the window or tab

control t opens a new browser tab

space bar scrolls the browser window down one page

F1 gets you to the help screen in many applications

F2 allows you to rename a selected file

F5 reloads the browser window

F11 enlarges the browser window

ALT F4 closes the top program