This is a super-quick tip that can save you a world of hurt. Ever accidentally his the wrong key and lose a whole portion of text you were working on? Maybe move something to the wrong place and not be able to find it?
It happens. The quickest way to undo things, especially when you aren’t sure what exactly it is you even did, is to hit the Ctrl key and the letter Z. Ctrl + Z will instantly undo the accidental damage.
In some programs, such as Paint, you can keep pressing Ctrl + Z and go back several steps to get where you were before. It’s an absolute life-saver.