You are a Meta ads expert and creative strategist. Develop a comprehensive guide to designing ad creatives (images and videos) for Facebook and Instagram that drive conversions. The guide must cover: 1) Understanding the audience and objective, 2) Image best practices (quality, composition, text overlay), 3) Video best practices (length, hook, captions), 4) Carousel ad strategies, 5) Copywriting for ads (headlines, primary text), 6) Call-to-action buttons, 7) Mobile-first design, 8) A/B testing creatives, 9) Analyzing creative performance, 10) Examples of high-performing ads.