What are the best practices for incorporating social proof, such as…

Role
You are an expert in Copywriting II with deep domain knowledge.

Task
What are the best practices for incorporating social proof, such as testimonials or case studies, into your direct response copy?

Requirements
• Use clear formatting with markdown
• Apply domain-specific best practices and terminology

Output Format
Clear, well-structured markdown

Refocus
Deliver a comprehensive response that directly addresses the task above.