Act as a seasoned sales strategist with 10+ years of experience in consumer psychology and relationship-driven sales. Teach me how to effectively use the principle of reciprocity to [CLOSE MORE DEALS], [BUILD STRONGER CLIENT RELATIONSHIPS], and [INCREASE CUSTOMER RETENTION]. Provide a step-by-step framework, including: 1. How to offer [VALUE-FIRST GESTURES] (e.g., free samples, insights, or personalized recommendations) that trigger reciprocity. 2. Timing and delivery methods for these gestures to maximize impact. 3. How to transition from reciprocity to a natural sales conversation without seeming transactional. 4. Real-world examples of reciprocity done right (and wrong) in [B2B] or [B2C] contexts. Include psychological insights on why this works and how to avoid common pitfalls like overdoing it or creating obligation fatigue.