1. Go to the “Home” tab and click on the “Rules” drop down
  2. Choose “Manage Rules and Alerts”
  3. Under “Email Rules” choose “New Rule” and under “Start from a blank rule” click on “Apply rule on messages I send.” Click “Next,” which will show conditions — you don’t need to choose any of these, just click “Next” again.
  4. On the final menu (the “Actions” page), check “Defer delivery by _ minutes” and fill in the blank. I choose two minutes, because it often takes me a minute to realize what I’ve forgotten!
  5. lick “Next,” and fill in any exceptions to your new rule.   Then, click “Next,” and click “Finish”


Reference: https://hbr.org/2015/07/prevent-email-horror-with-a-2-minute-send-delay