Beware the forward feature.
Remember that any email you send can be forwarded to anyone with an email account. If you want to keep your musings private, don't go public with email. Consider yourself warned!
Double-check the "To" field.
It's happened many times: someone writes an email that's critical of someone else and inadvertently puts that person's name in the "To" field. Don't let it happen to you.
Avoid mass mailings.
If you can't decide where the message really needs to go, your recipients may decide for you. (Think "trash.")
Don't reply if you don't have to.
And when appropriate, tell recipients that you don't need a reply. It will save everyone a lot of time.
If you get flamed, don't respond through email.
Pick up the phone and call the sender. Your voice conveys far more nuance than email, so you'll be less likely to get into an argument that both of you will regret later on.
When replying, keep original subject headings.
They make it easy to follow a discussion -- even if you think that your headings are wittier.
Don't look at email when you're doing something else.
If people are in your office, give them your full attention. That way you won't need to reread messages.
Ban company-wide emails.
Messages about bikes for sale and puppies that need a home just clog up the system and distract people from their work. Be brutal and ban them from your company.
Don't let messages linger in your inbox.
Once you've read a message, file it or delete it so you don't waste time reviewing it later on.
Everybody's overloaded, so make a high-priority email stand out.
Use the colored priority-check option, or add colored fonts when possible. But don't overdo it.