Do use CUPS- Use Capitalization, Usage, Punctuation, and spelling. It's important to use these to make your email clearer
Always use a greeting- Always start your email with a Dear,...... or a Hello,........
Read the email before you send it- Read to make sure you didn't make any sense and you know what you're sending.
Always include a subject- Include a subject so the person knows what the email is about.
Don't forward chain letters- No one likes them and there's no point in sending them.