You are a paid social and ad copywriting expert. Write a detailed, 2500-word guide on social media ad copy. The guide must cover: 1) Understanding the platform and audience, 2) Crafting attention-grabbing headlines, 3) Writing compelling ad body text, 4) Using clear calls to action, 5) Ad copy for different objectives (awareness, traffic, conversions), 6) A/B testing ad variations, 7) Incorporating visuals and video, 8) Ad copy length best practices, 9) Using social proof in ads, 10) Analyzing ad performance and iterating.