Write requirements for a simple word processor or spreadsheet. Start with some obvious functionality. Add only enough "bells and whistles" for it to be usable for beginners. Show this list to others, especially people familiar with similar applications. What features do they find missing that are important to them? How quickly does your list expand? What might you do to limit the size and the rate of growth of the features list?
2.
Discuss the requirements for your application with someone who has no experience with a similar product. How difficult is it to get useful feedback? Now show them (the simple features of) a working spreadsheet or word processor, as if it were your prototype. Does the conversation change? In what ways? Is the feedback now more or less useful than before they saw the prototype?
