Successful businesses solve a pressing problem for their customers. Identify and rank the main problems of your customers.
Interviewing customers helps you to collect and understand their problems. Card Sorting is a method that you can use in interviews (or other settings) to let people prioritize their problems.
People can feel very attached to brands or routines that they have been practising for a long time. Let them write a breakup letter helps you to understand what it is that would encourage them to switch to a new offer.
Search the web and any other valuable resources for data that helps you to understand your target market, growth trends and customer segments.