Key points for a successful email

In this lesson I learned how to write a business email, because I don't understood why is necessary to do a brief subject, because if you do a long one, or if you don't say exactly that you want, the reader may don't read the mail, and sometimes emails are very important.
In fact, we need to consider this points to do a successful email:

-Use less usual words
-Never use abbreviations
-do a short sign. Don't be pretentious.
-Be formal
-Be brief and straightforward.
-Do a paragraph by each idea, with that your email will be organized by key points.
-Be carefully with who will have a copy of the mail. Sometimes it's not necessary to send copies to thrird persons.
-Don't attach big files.
-You can try to be creative with the subject. I find some interesting ideas for a marketing email.

https://www.pinterest.com/explore/small-business-plan/