Nobody needs to memorize a hundred keyboard shortcuts. A few of them come up dozens of times a day, and learning those pays back the first afternoon you use them.
The Three That Pay Off First
Undo. Cmd + Z on a Mac, Ctrl + Z on Windows. It works almost everywhere: a deleted paragraph, a moved file, a cell you overwrote in a spreadsheet. Press it again to go back another step.
Reopen the tab you just closed. Cmd + Shift + T on a Mac, Ctrl + Shift + T on Windows. Closed the wrong browser tab? This brings it back, and pressing it again keeps going back through what you closed. It works in Chrome, Safari, Edge and Firefox.
Screenshot part of the screen. Cmd + Shift + 4 on a Mac, Windows + Shift + S on Windows. Drag a box around what you want, and you have a picture to drop into an email or a text. It beats describing an error message over the phone.
One Rule That Covers Most of the Rest
Most shortcuts that use Cmd on a Mac use Ctrl on Windows, with the same letter. Copy, paste, cut, save, print, find and select all follow that rule. Redo is the common exception: Cmd + Shift + Z on a Mac and Ctrl + Y on Windows.
The Full Sheet
We put forty-two shortcuts on one page, Mac and Windows side by side, so anybody in the office can find theirs. Print it and tape it beside the monitor until your hands remember it without looking.