The PQ4R method is an active learning strategy for studying that involves previewing material, asking questions, reading, reflecting, reciting, and reviewing. It is based on principles of learning and cognitive psychology and increases the amount of information recalled compared to more passive learning strategies. The method involves previewing chapters to identify key points, asking questions about the material, reading while answering questions, reflecting on and relating the content to prior knowledge, reciting the material in your own words, and repeatedly reviewing. It also suggests using the Premack Principle to motivate studying by allowing rewards like social media after completing study sessions.