Remember that old saying about first impressions -- think about how people's perceptions of you, us, me are set when you're not even in front of them. That would be through email... in the climate today where a great many of us entrust much of our communication to the email message it is very important to ensure we are putting our best foot, or perhaps our best key/s forward.
I remember coming across a website in recent years that had some great tips on this topic and there are plenty of articles and even websites given to Email... how to use it best, etc. 
I filtered through these to provide
you with the following tips/suggestions, sprinkled with my own experiences and observations -- offered from the hands of
one who has typed many, many an email message over the past decade!
1. Ask yourself is this message appropriate for email -- or should this be discussed/delivered on the telephone or in person? There are some messages that might be easier to send from your keyboard but really deserve a phone call. Remember that nuances, tone of voice, etc. are all more easily understood in person or when the recipient can hear your voice. A terse tone, sarcasm, etc. do not work well in an email.
2. Build an Email around just one topic or question. It is better to send more than one message than to load one email up with multiple, non-related questions or topics. It's more likely that all your points will get addressed as it is easier for the recipient to read more quickly and reply.
3. Use BCC instead of pasting many email addresses into the 'To:' field.
When addressing a message to a group of people, use the BCC (Blind Carbon Copy) address line. You put your email address in the 'To:' field. By using BCC, the recipient only sees two recipients: theirs and yours. If you paste everyone's email into the TO field, all your friends' email addresses are now subject to others' who may not have accessed it before (opening the door for spam and fraud)
4. Include an Accurate Subject. I still receive some emails with no subject or an inaccurate subject line. This can go unopened or mis-directed by your recipient (it is ok to change the subject if you're forwarding or changing the conversation in a reply). Many experts also encourage a short subject - keeping it less than 35 characters.
5. Keep it short and clear... Email is not the place for long diatribes. Email is ideal for quick and short communication - if you must supply more content, lots of text you should consider giving the recipient a table of contents and a summary at the top of your message.
When I send out emails to the families of the youth sports teams I coach, I always put a table of contents at the top -- this ensures at a quick glance folks know what is in the email, and can even use the subject (in bold) to find the information relevant to their interest.
6. Practice Good English When Sending Email. It's one thing if your email is a quick message to 
your best friend. But if it is a message for community or work, work to ensure the spelling and grammar are correct (if your email program does not have spell check - you could copy and paste your message into a word processor to run spelling/grammar check if it's a particularly important message). Avoid abbreviations unless they are clearly accepted by the recipients. I would have a hard time convincing my 17-year old son of this but most every business authority recommends not to use abbreviations such as BTW (by the way) and LOL (laugh out loud).
7. Avoid using All Caps and highly embellished text. You likely have heard by now that all caps in email is the same thing as shouting your message. If something is important you can _underscore_ that word or phrase for emphasis. And avoid sending messages with highly stylized fonts and attributes (colors, very large sizes, etc). They may not be successfully seen by some recipients and they can be garish to read through (ok, a personal bias there).
8. Don't forward virus hoaxes and chain letters If you receive an email message warning you of a new unstoppable virus that will immediately delete everything from your computer, this is most probably a hoax. By forwarding hoaxes, you use valuable bandwidth and sometimes virus hoaxes contain viruses themselves, by attaching a so-called file that will stop the dangerous virus.
The same goes for chain letters that promise incredible riches or ask your help for a charitable cause. Even if the content seems to be bona-fide, the senders are usually not. Remember when they are asking you to pass it along and it goes back to the originator - they have accessed a whole lot of email addresses to 'work' with (think spam, fraud, etc.)
9.
Read the email before you send it. Reading your email through the eyes of the recipient will help you send a more effective message and avoid misunderstandings and inappropriate comments. Ideally, reading the email out loud will help you quickly pick up any unclear or emotional phrases that may be misinterpreted.
Here is an additional resource for email Etiquette: Top Email Etiquette Rules for Kind and Considerate Messages
Now, since it's Friday - how about some office fun! I came across this post earlier this week and got a good laugh. Here are 32 photos that depict some of the best office pranks that colleagues have played on their co-workers: Best Office Pranks of All Time
Here is one of my favorites... a computer keyboard set in Jello! I wonder if that's Cherry or Strawberry? Wait 'til you see the mouse. Enjoy!
