When you compose an email message, there are some simple rules that you can follow to ensure that your emails make a positive impression, and get you the response you want. Email should be constructed and written so that the intended audience can read, understand and act on the message after the first time they read it. Subject Lines are Headlines
It grabs your attention, and it tells you what the email is about. Use a few well-chosen words, so that the recipient knows at a glance what the email is about. Be concise to the point
Do not make an email longer than it needs to be