Dave McClure outlines a 5-step model called AARRR for evaluating startup metrics. The model focuses on Acquisition, Activation, Retention, Referral, and Revenue. McClure emphasizes testing features to improve conversion rates at each step of the customer lifecycle and using metrics to iterate quickly through building, measuring, and improving the product and marketing. He also stresses removing underperforming features to focus on the few things that drive user happiness and business results.