Now that you know a bit about your competition, it is time to conduct some market research.  You will not be caring our this market research.  Instead you will need to create a market research plan.  The plan will need to include the following

A marketing problem or question. example, where customers shop, their size, income etc.

Secondary research, include a list of possible secondary sources to get the answers to your question

Primary Research: A list of at least 5 questions that you want answered specifically.

A plan for how you will ask those questions in either a survey (postal, phone, internet), face to face interview, focus group or a combination of many.  Include a rationale (reason) for why you will use that method to ask those questions.