Some of these shortcuts also work in browsers like Ctrl+A.
Alt+S: Save. Do this often so you don't lose your work or have to make an effort to click the Disk icon.
Ctrl+A: Select all of the text in the email, document, or anything currently open.
Ctrl+Z: Undo last action.
Ctrl+Y: Repeat last action.
Ctrl+Right Arrow: Jump to the start of the next word to the right.
Ctrl+Left Arrow: Jump to the start of the next word to the left.
Ctrl+Shift+Right Arrow: Select the next word to the right.
Ctrl+Shift+Left Arrow: Select the next word to the Left.
Shift+Down Arrow: Selects current line of text and downward with each arrow click.
Shift+Up Arrow: Selects current line of text and upward with each arrow click.
Ctrl+B: Bold selected text.
Ctrl+I: Add italics to selected text.
Ctrl+U: Underline selected text.
Don't let these lists overwhelm you. Identify which actions you do often and start learning one or two at a time. Remember, you can always find new shortcuts by pressing F1 to access the Help file and look up keyboard shortcuts.