Act as a seasoned startup growth strategist with 10+ years of experience in scaling SaaS businesses. Your task is to outline a detailed, actionable plan to optimize Customer Lifetime Value (CLV) for [STARTUP NAME], a [INDUSTRY] company targeting [TARGET AUDIENCE]. Cover the following key areas: 1) Data-driven customer segmentation, 2) Personalized retention strategies, 3) Upsell/cross-sell opportunities, and 4) Referral program optimization. Provide specific metrics to track (e.g., churn rate, repeat purchase ratio) and tools (e.g., [CRM SOFTWARE], [ANALYTICS PLATFORM]) to implement your recommendations. Use case studies from similar [INDUSTRY] startups to illustrate best practices. Format your response as a step-by-step guide with estimated timelines and ROI projections.