You need to know everything obtainable about your customers. This list will get you started. You will need their age, sex, marital status, income levels, education levels, geographic locations, where they shop, if they go to church, if they have kids, ages of children, political affiliation, what they like about your company, what they don't like, why they shop with you, what they value about your products/services, what they like the most/least about products/services, and whether prospects are unaware of your brand or products/services. Customers want you to know certain things about them and if you do, they will remain loyal to you as you take time to know them.
Analyzing the Market: You cannot afford to operate on the basis of assumptions about the market and customers. You need to conduct a thorough analysis of the prevailing market environments, your strengths & weaknesses and the existing competition. Study your target customers and get in_depth knowledge of their needs and preferences. Based on this, you can determine your marketing objectives and position your product suitably.