8.

Give these Gifts: EOM NNTR

If your email message can be expressed in half a dozen words, just put it in the subject line, followed by EOM (= End of Message). This saves the recipient having to actually open the message. Ending a note with "No need to respond" or NNTR, is a wonderful act of generosity. Many acronyms confuse as much as help, but these two are golden and deserve wide adoption.