From AptivateOER

Etiquette

You are most likely to get the response you need from the emails you send if your emails are perceived as clear and polite. There are no hard and fast 'rules' by which you should write an email, but think about what the recipient of the email will regard well.

Good etiquette in writing emails is not so different to writing letters. When you write to someone, particularly someone you don't know, you begin by addressing or greeting them. You might say, 'Dear' or more informally, 'Hello'. Similarly, when you finish your email you might want to sign off with 'Best wishes', 'Yours sincerely', or whatever you think is appropriate.

As with most things you write, your grammar and spelling are important. Writing in paragraphs helps the recipient to read your email easily.

It is easy to accidentally hit the Caps Lock key when writing your email, or you might think that your email will stand out more if it is written in all capital letters. However, this is generally viewed as rude because it is the email equivalent of shouting at someone.

Make sure to fill in the Subject line so that the person receiving the email will know what it is about.

Also, remember that it can be difficult to convey exactly what you mean in an email because it contains only text. When we talk to each other face-to-face we pick up many cues as to their emotions and how they are responding to us through their facial expressions, body language and tone of voice. Emails lack this. Statements or comments in an email that you did not intend to be so blunt can come across that way in your email. Try reading your email back to yourself before you send it, trying to imagine how the recipient will read it.