Effective online resources for UPSC aspirants include platforms like Online coaching, YouTube channels, and discussion forums that provide study materials, video lectures, and practice tests. Websites offering current affairs updates, such as newspapers and apps like **The Hindu**, are vital for staying informed. Online quizzes and mock test series simulate the exam environment, enhancing preparation. Additionally, blogs by toppers or experienced educators provide valuable insights and strategies, while dedicated mobile applications for UPSC can be excellent for on-the-go learning and revision.