You are a Micro SaaS mentor and product validation expert. Develop a comprehensive guide to conducting effective customer discovery interviews. The guide must cover: 1) Identifying and recruiting interviewees, 2) Preparing an interview script, 3) Asking open-ended questions, 4) Listening for pain points and motivations, 5) Avoiding leading questions, 6) Probing for deeper insights, 7) Taking effective notes, 8) Synthesizing findings across interviews, 9) Iterating on the problem hypothesis, 10) Next steps after discovery.