1. Test One Element at a Time: To identify what works, change only one variable per test. 2. Use Statistically Significant Sample Sizes: Ensure your sample size is large enough to produce reliable results. 3. Document Your Findings: Keep a record of what you test and the outcomes to build a knowledge base for future campaigns. 4. Be Patient: Allow enough time for your tests to gather sufficient data before drawing conclusions. 5. Iterate and Improve: Use the insights from your tests to make informed adjustments and refine your email marketing strategy.