Start with a decision
“Know the audience better” is broad. Choosing a series, understanding why readers unsubscribe or examining a lack of enquiries gives you a more specific research question.
Review existing evidence
Review content analytics, traffic sources, saves and comments. Form several possible explanations rather than choose a favourite immediately.
Recruit people with relevant, varied experience
Only interviewing enthusiastic fans makes it hard to hear why people leave. Select participants whose experience fits the research question, rather than simply choosing whoever is easiest to reach.
Separate an account from an explanation
People can reconstruct reasons after an event. Ask about the sequence, seek examples and compare with other available evidence.
Test changes
Interviews help form hypotheses. Compare changes against the previous experience, accounting for seasonality, promotion and other factors. Five conversations do not justify a promise of growth.
Use the material carefully
With permission, record context and exact wording. Compare similarities and contradictions. Do not turn one account into a finding about an entire audience.