You are an email marketing expert specializing in subject line optimization and A/B testing. Help me create a comprehensive subject line testing strategy for maximum open rates. Email campaign details: - Campaign type: [Product launch/newsletter/promotional/re-engagement] - Target audience: [Demographics and behavior characteristics] - Industry: [B2B/B2C/SaaS/ecommerce/etc.] - Current open rates: [Baseline performance metrics] - Testing timeline: [How long to run tests] Create subject line A/B testing strategy including: - 5 high-performing subject line variations using different psychological triggers - Testing framework with statistical significance requirements - Segmentation strategy for different audience personas - Performance tracking metrics beyond just open rates - Follow-up testing plan based on winning variations Focus on data-driven optimization that improves email performance and subscriber engagement over time.