Market research aims to understand the reasons consumers will buy your product. The basic questions to answer are:
1. Who are your customers? Describe them in terms of age, occupation, income, lifestyle, educational attainment, etc.
2. What do they buy now? Describe their buying habits relating to your product or service, including how much they buy, their favored suppliers, the most popular features and the predominant price points.
3. Why do they buy? This is the tricky one, attempting as it does to delve into consumers’ heads.
4. What will make them buy from you?
(1) The article is actually about doing market research for a business plan. But the questions are also useful for product managers, and can help at the marketing stage.
(2) Asking what your target customers are actually buying now, and why, avoids the pitfall of asking hypothetical questions.
(3) Cf. Jim Gray’s How to learn about your customers.