Generate a full detail guide on leveraging customer testimonials. The guide should be marketing-focused. It must include sections on: 1. The Psychology of Why Social Proof is So Persuasive. 2. Simple and Effective Ways to Ask for Customer Reviews. 3. Where to Strategically Place Testimonials for Maximum Impact (e.g., on sales pages, in ads). 4. How to Turn a Good Testimonial into a Great Case Study. Please include a supportive disclaimer.