Marketing involves determining products or services of interest to customers and developing a strategy for sales, communications, and business development. This generates an underlying strategy for techniques like sales, business communication, and developing business. After World War 2 when supplies were low, production was the focus, but later an oversupply led to "hard sell" tactics to increase sales. The sales force is one of a company's most valuable resources and should be designed around customers. Sales promotion directly links brand plans to sales decisions for alignment of strategy and execution.