
Statistics from April 2010 estimate the number of emails sent per day (in 2010) to be around 294 billion. 294 billion messages per day means more than 2.8 million emails are sent every second and some 90 trillion emails are sent per year. Around 90% of these millions and trillions of messages are but spam and viruses. The genuine emails are sent by around 1.9 billion email users. Probably email has become an ineffective method to deliver information, primarily because it is overused and misused hence to live up the importance of emails one should follow certain things that everyone needs to avoid.
Don't use email for a conversation.
Email works well when you need to deliver or push out information. It can help people make decisions.
But email is NOT an effective platform for holding back-and-forth dialogue.
Don't use email to issue ultimatums, challenge, or pressure.
Email is one of the worst and most risky way to exert power or intimidate people It leaves a permanent trial, which when you're angry, can be devastating to your career.
Using email to contribute to negative feedback, to sternly argue your point, or to deliver bad news can be catastrophic. That's because it's impossible to read body language via email and the written word can come off sounding harsher than we intend.
Email is an indispensable tool in today's workplace when used wisely; effective leaders do most of their talking the old-fashioned way - face to face or over the phone.

Humor may not be well communicated via e-mail. There are no nonverbal cues from which other people can deduce any underlying meaning to your message.
E-mail is often misinterpreted. Your e-mailed words live forever. They get forwarded. They'll practically outlive you and take on a life of their own.
Don't send attachments without scanning them for viruses.
Don't send attachments if you can possibly avoid it.
Don't forget to update
Don't convert print promotions directly to e-mail blasts
Don't overcomplicate your e-mail creative
Don't over mail your list
Don't under mail your list
Don't send sensitive e-mail unencrypted.
E-mail is not private and shouldn't be used as a substitute for the privacy of traditional mail.
Don't send anything in e-mail that you wouldn't want your boss, your spouse, your mother or your kids to read. E-mail is not private.
Get to the point right away.
When asking a question, be sure to ask the question.
Specify who should respond.
Don't ignore your reports and front line
Don't say everything in the subject line
Don't be clueless (by having no call to action)
Don't forget to be timely
HEnce the Next Time you write an email do not forget to keep in mind the above things