Common resources used by candidates to prepare for UPSC exams include standard NCERT textbooks, reference books by renowned authors, and periodicals like newspapers and magazines. Many candidates rely on curated study material and online platforms for mock tests and interactive learning. Additionally, coaching institutes often provide tailored study guides and notes that help streamline preparation. Utilizing these varied resources allows candidates to cover the extensive syllabus effectively and gain comprehensive understanding and insights necessary for success in the UPSC exams.