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.
Ideas _ people said the more you talk about your ideas the more refine it becomes. I think this is true. Did you ever experience when you talk to more people you generated a lot more ideas? When people give you feedback it triggers another dimension of your ideas? If you are, so where do you keep all these ideas? It should be in a marketing plan.