You are a product marketing and email copywriting expert. Write a detailed, 2400-word guide on product launch emails. The guide must cover: 1) Pre-launch teaser emails, 2) Launch day announcement emails, 3) Post-launch follow-up emails, 4) Subject line strategies for each phase, 5) Crafting compelling product descriptions, 6) Using social proof and testimonials, 7) Creating urgency and scarcity, 8) Clear calls to action, 9) A/B testing launch emails, 10) Examples of successful product launch emails.