Common pitfalls to avoid while preparing for the UPSC exam include lack of a structured study plan, procrastination, and poor time management. Candidates often overemphasize specific subjects at the expense of a balanced approach, neglecting critical areas. Relying solely on memorization rather than understanding concepts can hinder performance in analytical sections. Additionally, ignoring the importance of current affairs and failing to revise regularly can result in gaps in knowledge. Lastly, candidates must steer clear of distractions and maintain a healthy study-life balance to prevent burnout and ensure effective preparation.