Recommended online platforms for UPSC preparation include Unacademy, BYJU'S, and Insights on India. These platforms offer extensive resources such as video lectures, test series, and interactive quizzes to aid in understanding complex topics. Websites like ClearIAS and StudyIQ provide study materials, notes, and preparation strategies tailored for aspirants. Additionally, utilizing platforms like YouTube, where educators share insights, can significantly enhance the learning experience. Engaging with online communities also fosters a sense of shared learning.