1. A/B Testing: Conduct A/B tests with different button designs to see which one performs better. Test variations in color, size, text, and placement. 2. User Feedback: Collect feedback from recipients to understand their experience and preferences regarding button design. 3. Analytics: Use email marketing analytics to track CTR and conversion rates. Analyze the data to identify patterns and areas for improvement. 4. Heatmaps: Implement heatmaps to see where recipients are clicking within the email. This can provide insights into button visibility and effectiveness.