The subject line: is essential and must reflect the subject of your message.

Identification: Always include your address and telephone number.

When in doubt, leave it out:

This pertains to messages you're replying to: repeat just enough of the original to jog the sender's memory.

The leave-it-out rule also pertains to racial slurs, swear words and other harassing, inflammatory language Contribute wisely. Nobody wants to waste time reading "Me too" messages.

Don't send a message when you're angry: The immediacy of e-mail makes it possible to send emotional replies that you may regret 10 minutes later. If you feel angry, or find yourself composing a particularly sarcastic or caustic message, click on "Draft" and let it sit for a while. 

Re-read your message after you've cooled off and can consider the situation more objectively.

Be as polite as possible, terseness can be taken as hostility.

The easiest way to start a flame war is to malign someone you don't agree with.

Don't reply to "all recipients" unless they all need to see your reply.

Think short: Limit the message to three paragraphs, tops, each with no more than four sentences. If you must include more, introduce points with short previews--for instance, "Deadline? Did I miss it?" Be concise and precise. For E-mail messages, shorter is better.

Be very careful: When you respond to e-mail by hitting "Reply to Sender." It's easy to mistakenly hit "Reply All," sending your message to unwanted recipients.

Follow the golden rules we learned as children: Respect others; there is simply no excuse for bad manners.

Proofread your messages before sending. Typing can get sloppy when responding quickly, and you want to keep your messages looking business-like and precise
Keep it simple:

There is nothing wrong with personalizing your e mail, however, try to avoid the fancy formatting, flowery backgrounds, and gaudy colors that new versions of e-mail software allow. Many people still use e-mail programs that support plain text only.

Don't type in all capital letters -- IT LOOKS LIKE YOU'RE SCREAMING.

Don't hide behind your computer. E-mail is great for some things, but it's a cop-out for situations that need a personal touch. Pick up the telephone.

Check spelling and grammar. Set your Outlook tools to check spelling before sending. It is simple and makes you more professional.
 
Read it out loud to check the grammer.

Only include relevant return text. There is a tendency to just hit "return" on a message and type in a fast answer. This is not the best way. If someone sends off a single question embedded in a larger message they do not want to see the whole thing again. In many cases, the best way to answer a message is to eliminate return text altogether and address the question in a simple, declarative sentence. That way, the recipient doesn't need to stumble through the original message to remember the question.

Each message costs money. It takes time, energy and resources to support e-mail, always keep that in mind.

Know your recipient. Different people have different ideas of what is acceptable. Find out and respect each person's wishes.

Be careful, about your use of irony or even some forms of humor, which can be misinterpreted. Unlike face-to-face meetings or phone conversations, there are no visual or oral clues to provide a sense of what is going on.
 
Remember, body language is 90% of the communication process. Always keep that in mind.
Don't send copies, of e-mail to people unless they need to be copied. In addition to cluttering up their mailboxes, it can place them in an awkward position, making them feel as if they have to do something with the information. It also can be intimidating to the main recipient.

Be careful with your address book. It's easy to accidentally send a message to the wrong person. It could be embarrassing.

Don't send attached files unless you have a very good reason and only if the person is expecting them. Attached files -- Word documents, spreadsheets and software programs -- can carry viruses and clog up network bandwidth.
 
They take a long time to download which can inconvenience the person who receives them.
Introduce yourself: Briefly describe who you are if the recipient doesn't already know.

Don't "cry wolf." Avoid "Urgent" or "Priority" unless it really is.

Use "receipt requested" sparingly. Some people view it as a sign of distrust. It is okay to use it if you have reason to question whether the person will log on to receive your message.

Timeliness: Check your mail regularly and, respond to people who write to you.
Finally, when in doubt, rule it out.