User interviews are the backbone of qualitative research, but most are conducted poorly — leading to confirmation bias, social desirability effects, and superficial insights. This article covers the complete interview process: recruitment and screening, writing a discussion guide, mastering probe questions, active listening techniques, and synthesizing findings. Key techniques include the 'five whys' for depth, critical incident technique for specificity, and the 'mom test' principle of asking about behavior rather than opinions. It includes a template discussion guide and common interview anti-patterns to avoid.