Common mistakes made by UPSC aspirants often include poor study habits, such as procrastination, inadequate revision, and reliance on outdated materials. Many overlook the importance of current affairs, which are crucial for both prelims and mains. Additionally, candidates might attempt to cover vast areas superficially without mastering key concepts, leading to confusion. Effective preparation involves systematic study, regular self-assessment, and the ability to adapt strategies based on strengths and weaknesses.