UPSC aspirants can improve their retention of vast information through effective study techniques such as active recall, spaced repetition, and mind mapping. Active recall encourages candidates to test their knowledge regularly rather than passively reading notes, enhancing memory consolidation. Spaced repetition involves revisiting material over increasing intervals, promoting longer-lasting retention. Additionally, creating mind maps helps visualize connections between topics, facilitating easier recall. Incorporating regular revision sessions into study schedules ensures systematic strengthening of memory. Lastly, healthy habits like adequate sleep, nutrition, and physical exercise complement these techniques, improving overall cognitive function and information retention.