Once you have chosen your testing methods, you need to plan and execute your tests in a systematic and rigorous way. To begin, you should formulate clear and testable hypotheses that express what you expect to learn from your tests. For example, "We believe that adding a testimonial section to our landing page will increase the sign-up rate by 10%." Next, select a representative sample of your target customers that matches your customer segments and personas. This includes deciding on the sample size, the sampling method, and the criteria for inclusion and exclusion. Then, design your tests according to the best practices of your chosen methods. For example, if you are doing A/B testing, make sure that you have a control group, a variation group, a clear variable, and a random assignment. After that, run your tests for a sufficient period of time while collecting and recording data accurately and consistently. Monitor for any errors, biases, or anomalies and adjust them if necessary. Finally, analyze your data using appropriate statistical tools and techniques to compare results with hypotheses. Also look for patterns, trends, and insights that can help you understand your customers and product better.