Several elements contribute to making a headline compelling:
1. Clarity: The headline should clearly convey what the email is about. Avoid ambiguity. 2. Relevance: It should be relevant to the recipient's interests and needs. 3. Urgency: Create a sense of urgency to encourage immediate action. 4. Curiosity: Spark curiosity without being overly vague. 5. Value: Highlight the benefit or value the recipient will gain by opening the email.