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.
So in order to bring success to your business, you need a strategic marketing plan. Strategic plans are classified according to their time frame to long, medium and short_ term plans. Usually long_term plans tend to be between 5┦ years at corporate level, medium_term plans 2λ years and short_term consists of a time period ranging from 6 months to 1 year.