The most common research mistake is starting without a clear question. Research is valuable when it informs a decision you actually need to make.
Decision First
Write down the decision: should we build this feature, should we target this segment, should we change our price? Then ask what you would need to believe to choose each option. These beliefs become your research questions.
Assumptions and Risk
List the assumptions behind your idea. Rate each by how uncertain it is and how damaging it would be if wrong. Focus research on assumptions that are both uncertain and high impact.
Choosing Methods
Interviews explore why and how. Surveys measure how many. Experiments test what people actually do. Analytics shows what users do in your product. Match the method to the question: you cannot learn why from a survey tick box, and you cannot measure prevalence from five interviews.
Scope It Small
A focused round of research, such as eight interviews over two weeks, is usually more useful than a large project that takes months.
Exercise
Write one decision you face, list three key assumptions and rate each by uncertainty and impact.