☆Do some further reading and report what you have learned. The following link may be of help.

1. Email Tips: Top 10 Strategies for Writing Effective Email

http://jerz.setonhill.edu/writing/e-text/email/

2. Email Etiquette

http://www.dailywritingtips.com/email-etiquette/

3. Why Writing Email Is a Skill—and Why Learning It Matters

http://business.tutsplus.com/articles/why-writing-email-is-a-skill-and-why-learning-it-matters--cms-20655