Effective resources for developing a thorough understanding of Indian history for the UPSC include a variety of textbooks, online courses, and documentaries. Standard reference books like India's Struggle for Independence by Bipin Chandra or A History of Modern India by Sumit Sarkar provide structured insights. Incorporating online platforms like Unacademy or Coursera offers diverse lectures and discussions. Moreover, engaging with visual resources like historical documentaries can enhance retention. Regular interaction with previous question papers helps identify crucial topics and trends, reinforcing the candidate's understanding and readiness for the examination.