Common pitfalls during UPSC exam preparation include inadequate time management, lack of a clear study plan, and neglecting current affairs. Many candidates often focus excessively on specific subjects and ignore others, leading to an imbalanced preparation. Additionally, underestimating the importance of answer writing practice can hinder performance in the Mains. Another misstep is becoming overwhelmed by the vast syllabus, which can discourage consistency. It's crucial to maintain a balanced approach, stay updated on current events, and regularly practice answer writing to evade these pitfalls.