Candidates assess their performance in mock tests for the UPSC by reviewing their scores, accuracy, and speed in solving questions. After taking a mock test, aspirants should analyze their results to identify strengths and weaknesses. It is important to focus on areas with low performance and revise relevant topics. Regular mock tests also aid in familiarizing oneself with the exam format and developing time management skills. Additionally, comparing scores across different tests helps track improvement over time, ensuring a structured approach to tackling the exam's challenges.