When selecting study materials for UPSC, candidates should consider relevance to the syllabus, credibility of the authors, and updates for current affairs. It's crucial to prioritize sources that align directly with the exam's requirements, such as standard textbooks and reliable online platforms. Evaluating materials based on reviews from previous students can help identify effective resources. Additionally, balancing core subjects with current and contextual studies enhances understanding. Candidates should also ensure a comprehensive approach, covering both theoretical concepts and practical applications to meet the exam's demands effectively.