From the Experiment Cookbook
What lean experiment to run?
How to decide what your next validation experiment should be?
When you’re preparing to validate assumptions, and are looking for a good experiment to run that will give you the results you need, it can sometimes be difficult to make a good choice.
Should you create a landing page? Interviews? Or a detailed user test? Do you want to have quantitative data to make your next decision? Or are you looking for rich feedback?