If you work in an office, chances are you rely on e-mail to get your job done. Maybe a little too much, according to Tim Sanders, a former chief solutions officer at Yahoo Inc.

Sanders spent more than 10 years at Yahoo researching people and their e-mail usage. His findings were striking: e-mail accounts for 90 per cent of all work communications but we're only able to properly make sense of seven per cent of those messages. The average worker will spend four to five hours a day reading and responding to e-mails, just to keep up.

"We've learnt that e-mail is the number 2 source of stress at work, second only to change," Sanders said.

E-mail is the least effective way of communicating, Sanders says, partly because the medium is not good at conveying nuances — it's only good for relaying simple information. Sanders says that leads to more misunderstandings, more time spent clarifying, and more confusion, cutting into productivity.

Sanders's research led him to write the book The Dirty Dozen Rules of E-mail Etiquette. His tips for using e-mail effectively at work include:

Don't give bad news over e-mail

If you're going to offer criticism, don't do it over e-mail. Sanders cites a University of California study that shows people rely on face-to-face communications or hearing your voice to decode your intentions. Only seven per cent of cues are sent in your written word. Sanders says if you don't want your message to be misconstrued, pick up the phone.

Don't copy an e-mail over someone's head

When you start copying multiple people on your e-mails, you will do nothing but hurt your relationships and this escalation will not help you get things done. Sanders says when a boss is copied on an escalation note from one of their direct reports, 85 per cent of the time they don't read it. They will delete it 70 per cent of time as soon as they see the subject line.

Stamp out 'Reply to All'

Sanders's research suggests that "Reply to All" makes up about half the e-mail that is sent around the world. However, it's only useful one out of 10 times. People who receive e-mail of this kind are more likely to tune out the sender - not just for that e-mail but anything else they send.

Think before you forward

The forward button in e-mail makes millions of people 21st century tattletales, Sanders says. Don't forward something without permission. Do make it clear when sending an e-mail that you don't want it forwarded. Write "Do not forward" at the top.

Never pre-address an e-mail; leave the safety on

Have you ever sent an e-mail and the minute you sent it, had a sinking feeling that your life would change after sending it, or received an e-mail that you made you mad?

People send "mad mails" because they often don't realize how quickly you can press the send button. Sanders suggests deleting the recipient's e-mail address because when you hit "send," instead you'll get an error message, which gives you time to consider whether you really mean to send the e-mail.

Don't send e-mail at unprofessional hours

If you're a boss, don't send e-mail to someone you work with at a time you wouldn't call them on a phone to talk. While it just might be more convenient for you to send an e-mail at that time, you're sending your employee the wrong message. Employees get snapped out of their necessary recovery and rehab time when they get e-mails after hours.

Sanders says if you communicate during normal working hours, you will change the culture, mood and burnout rate in your organization. Employees might not start looking for other jobs.

Don't write War and Peace over e-mail

If you can't fit your e-mail into the preview pane, you need to pick up the phone and have a genuine conversation. Keep it short and simple.

Sanders suggests smart subject lines that tell the recipient what you want them to do. Put the why, what and when in the e-mail briefly.

Break the thread with a phone call

According to research, the number of back-and-forth e-mails on the same subject is directly related to a decrease in the quality of our communications.

One three-minute phone call is three times more effective in resolving an e-mail issue than an e-mail that takes four hours to write.

Sanders suggests that if the message goes back and forth more than three times, call that person and settle it over the phone.

Don't send an e-mail to someone you could hit with a rock

Get out of your chair to talk to the people who sit near you - don't substitute e-mail for face or phone time. Research indicates that when you replace face time with an e-mail, you experience a breakdown in your ability to cope with stresses and strains in your work environment.

Sending an e-mail to someone who's sitting next to you suggests that it's not worth the effort to get up and walk a few paces to talk to them.

Don't be cryptic in your e-mail response

Proper use of grammar, spelling and punctuation influences people's perception of your intelligence, educational background and how much money you make every year. E-mail is inefficient at conveying complex messages, so the more you review and edit your e-mails before you hit send, the less are you to be misunderstood.

Don't be so heavy in your e-mails

Attachments can bog down the system. You should ask permission before you send a large file to someone. It's not a gift to give someone a heavy e-mail any more than it is to give them a T-shirt with your corporate logo on it.

Use the CLEAR system at work

Sanders has devised five questions to maintain e-mail productivity you should ask yourself before you hit send:

• Connect to your job: Is the e-mail connected to the recipient's job? … Does it have anything to do with their role or jobs inside the company?
• List: Give them a list of exactly what you want them to do about the information in your e-mail.
• Expectations: What are you trying to accomplish with the e-mail?
• Avenues: What are my avenues to help you get something done?
• Return: What is the return on investment? Whether I'm reading what you're doing for the next five minutes or the next quarter, tell me what is my return on attention. The more you admire and respect attention, you'll find others will reciprocate to you, too.