Effective revision techniques for the vast UPSC syllabus include creating a structured study schedule and utilizing techniques like active recall and spaced repetition. Candidates should consolidate their notes regularly, engage in mock tests, and focus on important themes across subjects to enhance retention. Group discussions can also facilitate deeper understanding. Incorporating visual aids like mind maps and charts can make complex topics easier to grasp. Regular revision sessions should align with the syllabus to ensure comprehensive coverage of the material.