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.
A strategic marketing plan is the secret behind every successful business. If you are not satisfied with the results of your marketing tactics, consult a professional marketing agency that can devise a targeted marketing plan to help improve your business and increase the sales. A reliable and comprehensive online local business directory is your best source for finding a capable and experienced marketing expert servicing your area.