This document proposes the concept of "thinking in thinking" as a way to improve one's thinking abilities. It uses the analogy of training an athlete to suggest that without practicing thinking about how to think (thinking in thinking), one's mental abilities cannot progress. It provides examples of how the brain processes data when solving a math problem or using a calculator, and suggests that increasing one's brain speed through focused thinking in thinking can enhance one's thinking skills. The goal is to better understand and control one's own thought processes in order to achieve success.