The summary.
THE SHORTCUT MOST PEOPLE DO NOT KNOW
Paste without formatting. It prevents pasted text arriving in the wrong font and ruining a document.
Learn a few shortcuts at a time until automatic, not fifty at once.
USE THE RIGHT MOUSE BUTTON
It answers "what can I do with this?" in one action, and most people never use it.
DISABLE NOTIFICATIONS THAT DO NOT REQUIRE IMMEDIATE RESPONSE
Each interruption costs far more than the moment it takes, and switching between tasks is slower than it feels.
Check messages at set times rather than continuously.
ACCURACY BEFORE SPEED WHEN TYPING
Corrections cost more than fast typing saves. Not looking at the keyboard makes the largest difference.
MAKE TEMPLATES OF ANYTHING YOU PRODUCE REPEATEDLY
And protect them, so a completed document does not overwrite the template.
A SECOND SCREEN IS THE MOST EFFECTIVE PRODUCTIVITY PURCHASE FOR MANY PEOPLE
Most work involves referring to one thing while producing another.
RAISE YOUR LAPTOP AND USE A SEPARATE KEYBOARD
A laptop flat on a desk forces looking down and reaching up, and is the commonest cause of discomfort.