REMEMBER that your customers are people too and they deserve to be treated in the same way you treat colleagues and staff. Listen to them and pay attention to what they tell you.
Feedback from people who use your product, or whatever service it is you give them, is the best way of knowing your market and crucially, that you are providing what the customer wants.
If you always put the customer first, then your decisions as a leader or a manager are unlikely to be too wide of the mark.