Effective study techniques for mastering vast UPSC syllabi include the use of active recall, spaced repetition, and creating concise notes. Breaking the syllabus into manageable sections allows for targeted studying, while regular revision reinforces retention. Time management strategies, such as the Pomodoro technique, help maintain focus. Group discussions and teaching concepts to others can also solidify understanding. Utilizing varied study materials ensures a comprehensive grasp of the syllabus, enhancing overall preparation.