Email etiquette establishes your credibility and helps communicate your message. Etiquette is essential whether your email is a short message or a complex legal analysis. Below are emailing tips and links to articles and books for further study.
Abbreviations - avoid abbreviations
Addressing - use bcc instead of cc for long distribution lists.
Brevity - keep messages short
Caps - don't use all caps
Calling - substitute calls with meetings to avoid misunderstanding or controversy
Subject - use appropriate subject lines