Overthinking is a problem faced by many students where they daydream and lose focus by getting lost in their own thoughts. The document provides some simple ways to stop overthinking such as focusing on positive outcomes rather than negatives, using time productively for study instead of overthinking, changing one's view of fear, and taking action instead of waiting for opportunities while overthinking. In conclusion, overthinking leads people to stress themselves by imagining all possible situations and lose control of their thoughts, so it is best to focus on what you can control in the present.