Case studies can be effectively used in UPSC mains preparation by providing real-world scenarios that allow candidates to apply theoretical concepts. Analyzing case studies fosters critical thinking and aids in understanding complex issues related to governance, public administration, and socio-economic challenges. Candidates should practice writing case study analyses, focusing on identifying problems, suggesting feasible solutions, and considering implications. This approach enhances problem-solving skills and prepares aspirants for interview questions, thereby improving overall performance in the examination.