Keep messages short
Emails are best suited for quick, day-to-day correspondence. If your message is very important or very long (more than 250 words, or half a printed page) consider sending it as a Word file or making it a memo. Because people receive so many emails daily, a printed document may add weight to what you are saying.
Use informative subject lines
The recipient of your email should be able to get the gist of your message by scanning the subject line. “Today’s meeting” is more informative than “Meeting,” and “Today’s meeting canceled” is even better.
Include the original email or some other type of context when replying to a message, even if you respond immediately. Most people get dozens of emails daily, and a simple “Yes” or “No” without context can be confusing.
Be conscious of screen length
Keep your messages short and be conscious of screen length. Have the most important information appear right away, so the reader doesn’t have to scroll down to find it.
Break up paragraphs
It’s hard enough on the eyes to read from a computer screen without having to slog through a long, dense paragraph. When in doubt, chop things up.
Because emails are often conversational in tone, it is tempting to think of them as a different species from other business documents. But while emails may be less formal than other documents, they shouldn’t be less professional. Follow the same conventions you would in any other business correspondence:
Write in complete sentences
Capitalize the beginning of sentences
Use proper punctuation
Proofread before sending. If it’s a particularly important email, print it and proofread it in hard copy.
Two other tips:
Avoid using all caps. Not only are they equivalent to screaming, but they can also be difficult to read.
Do not use emoticons (smiley faces, etc.). They’re fine for personal emails, but not appropriate in most business contexts.
Assume your email will be forwarded
People other than the intended recipient may see your email. Emails are often forwarded, and in some cases, companies can even retrieve deleted messages. A good thought to hold as you write an email is to omit anything you wouldn’t want to be exposed on 60 Minutes.