Make sure you don't send messages from 1981.
If you don't know how to say good-bye at the end of an email, there's one thing that will almost always be appropriate. Thanks.
Without a line sub-scripted "sign here", how do you decide where to place your email signature? Look here.
Tell it like it is. Have you notices how people who you understand perfectly well when you listen to them become cryptic when they start writing?
Smaller is more beautiful, at least when it comes to email attachments. So make files smaller before your send them via email.
"Me too" is not enough content, but too much annoyance.