Act as a seasoned Product Manager with over 10 years of experience in user research and product development. Provide a detailed guide on best practices for conducting user interviews to gather actionable insights for [product type/app/service]. Include specific tips on how to prepare for the interview, craft effective questions, and create a comfortable environment for participants. Highlight techniques for avoiding [common biases], such as confirmation bias, and ensuring diverse user perspectives are captured. Additionally, explain how to analyze and synthesize interview data to inform [key product decisions], such as feature prioritization or UX improvements. End with practical examples of how these practices have led to successful outcomes in previous projects.