Effective email communications require well-written subject lines that clearly convey the email's topic. Subject lines should include any relevant project names and dates for recurring emails. The body of the email should state the purpose upfront, use paragraphs to separate ideas, and specify any desired outcomes or next steps. Tone and formality should be tailored to the audience, and emails are not suitable when information is long, confidential, or emotionally charged. Key tips include using proper grammar, proofreading before sending, and avoiding all-caps or overuse of priority and reply-all functions.