Ask as many questions as possible, then try to find sources to answer these questions. Such as, who needs your product? If hospitals, how many hospitals are there? How many doctors? How many women or children are in this market? What percentage would need the product, etc.
Search for articles which may show consumer preferences or innovation trends and adoption. Many surveys, polls, consumer behavior studies are published. Determine issues, concerns, or trends by scanning headlines or article titles from trade publications. Also see trade publications which publish product comparisons or announcements