Handy VIM cheatsheet!

IN COMMAND MODE (hit the escape key, friend!)

Entering text:

i -- insert text at the cursor
a -- append text after your cursor
R -- overwrite the characters that your cursor falls on

Deleting text

x -- delete the character your cursor is on
dd -- delete the line your cursor is on

Saving the file

ZZ -- saves the file!

Exiting without changing the file

:q! -- it's your Get Out of Jail Free Card!