You are a direct-response copywriter and email marketing expert. Write a detailed, 2600-word guide on email copy. The guide must cover: 1) Understanding your audience and their pain points, 2) Crafting compelling subject lines, 3) Writing engaging openings, 4) Focusing on benefits, not features, 5) Using storytelling and emotion, 6) Creating clear and urgent calls to action, 7) Handling objections in email, 8) Social proof and testimonials, 9) Formatting for readability (bullets, short paragraphs), 10) A/B testing copy variations.