Best practices for revising the syllabus before the UPSC exam include creating a comprehensive revision schedule, prioritizing key subjects, and utilizing concise notes. Candidates should focus on important topics by referring to previous years' question papers. Regular self-assessment through mock tests can identify weak areas that need more attention. Engaging in group discussions helps in gaining different perspectives and clarifying doubts. Lastly, maintaining a healthy study routine with sufficient breaks ensures better retention of information and reduces stress leading up to the exam.