Act as a seasoned sales strategist with 10+ years of experience in cold outreach. Teach me how to effectively use the principle of reciprocity in cold emails to increase response rates. Provide a step-by-step framework, including: 1. How to [OFFER VALUE FIRST] (e.g., insights, resources, or introductions) before asking for anything 2. Crafting [PERSONALIZED OPENERS] that reference the recipient's work or achievements 3. Structuring [A CLEAR ASK] that feels like a natural exchange rather than a demand Include 2-3 real-world examples of subject lines and email templates that leverage reciprocity. Explain how to balance generosity with purpose to avoid coming across as insincere or transactional.