The best ways to condense information for UPSC revision include creating summaries, using mind maps, and employing flashcards for quick retrieval of facts. Prioritizing critical points and summarizing lengthy texts into concise notes can increase efficiency. Developing tables or charts helps visualize relationships between concepts. Regular revision sessions, spaced out over time, help reinforce knowledge. Additionally, group study sessions where candidates teach each other can enhance retention. The aim is to convert vast information into manageable formats that facilitate effective revision and quick recall during examinations.