This paper outlines a robust approach to developing customer segmentation. If you make a product, have a service, market or sell, customer segmentation is relevant and important. The phases of development of customer segmentation, from planning through to implementation and ongoing reviews are outlined, together with the types of occurrences that can trip you up along the way. The generic approach described is relevant across industry sectors, both product and service organisations. Segmentation is a key input to the development of marketing strategy, bringing simplicity to your marketing plans.