A couple of things I think are important for the body text of emails:
- Have short paragraphs: email paragraphs should be more like bullet points.
- Put a purpose statement towards the start of the email.
- Embolden the most important text: the relevant actions and dates.
- If it's really important, follow it up with a phonecall.
- Make sure you include a warm salutation and valediction.
- Put separate stuff in separate emails. Don't hide an invitation to dinner in an email about church rosters.