Common resources used by successful UPSC candidates in their studies typically include NCERT textbooks, renowned reference books, and online platforms offering current affairs updates. Candidates often rely on Indian polity books like Lakshmikant and resources on economic surveys for comprehensive knowledge. Online courses and coaching institutes present structured guidance and materials, while dedicated newspapers and magazines provide crucial real-time information. Utilizing revision sources like summary notes and question banks greatly benefits retention and practice. Successful candidates may also engage with audio-visual materials, ensuring diverse learning methodologies that cater to various learning styles and enhance understanding.