Act as a seasoned email marketing strategist with 10+ years of experience in crafting high-converting upsell campaigns. Your task is to outline a step-by-step upsell email sequence for [PRODUCT/SERVICE], targeting [TARGET AUDIENCE] who have already purchased [INITIAL PRODUCT]. The sequence should include [NUMBER] emails, each with a clear objective (e.g., building trust, highlighting benefits, creating urgency). For each email, provide: 1. A compelling subject line 2. A personalized opening hook 3. Key benefits tailored to [CUSTOMER PAIN POINTS] 4. A strong CTA with [OFFER DETAILS] 5. A follow-up strategy for non-responders Include psychological triggers like scarcity, social proof, and exclusivity. Ensure the tone aligns with [BRAND VOICE] and the emails are optimized for [DEVICE TYPE].