Here are a few basic guidelines I find useful and that I keep coming back to:
A clear subject line. For me, the subject line is the reason I open an email or not. So Instead of saying “follow up to our conversation” it might be better to be more specific like “questionnaire attached” or ‘the proposal you requested".
A greeting such as “Hey", "Yo" or "Hiya" may not be professional, depending our your audience. Try using "Hi" or "Hello" instead. Or if you need to be more formal you could use “Dear [Name]",
Beware of humor: it doesn’t translate well onto the page. Often a humorous effect comes from tone of voice or body language, in addition to the words. Without those clues, your reader may misinterpret the humor, not realize it’s a joke, or think it’s cynical or sarcastic. And that doesn't serve anyone.
Proofread before you send the email. A message full of spelling errors makes you look sloppy or careless. Sure, a mistake can slip in now and then but if you constantly send out messages with mistakes, it can damage your image.
Don’t send an email when you’re angry. You can write the message, but save it and read it again and make adjustments when you’re calmer so that the message is neutral.
Do you have other favorite tips that help you present yourself professionally and encourage people to read your emails? Let me know!