43 Folders has a solid article on Writing sensible email messages. I especially back their advice to write a great subject line:
Compose a great “Subject:” line that hits the high points or summarizes the thrust of the message. Avoid “Hi,” “One more thing…,” or “FYI,” in favor of typing a short summary of the most important points in the message:
- Lunch resched to Friday @ 1pm
- Reminder: Monday is "St. Bono’s Day" — no classes
- REQ: Resend Larry Tate zip file?
- HELP: Can you defrag my C drive?
- Thanks for the new liver — works great!