Interviewing buyers, customers, and users is essential for many B2B roles, including product management, portfolio marketing, and customer engagement. Forrester has identified best practices for preparing, conducting, and following up interviews. Interviewees should be carefully vetted based on firmographic criteria, job role, experience level, and other relevant attributes. Depending on the purpose and goal of the interviews, different functions will lead or be involved in the effort, though there are commonalities across functions that can lead to productive research outputs. In this report, we describe best practices for efficiently and effectively conducting customer interviews.