Common mistakes UPSC aspirants should avoid include poor time management, neglecting current affairs, and sticking too rigidly to a single resource. Overloading on information or trying to master every subject without strategic focus can lead to burnout. Candidates often underestimate the importance of practicing answer writing, leading to ineffective responses during the mains. Furthermore, limiting study to textbooks without engaging with the broader context can hinder comprehension. Maintaining a balanced approach and regularly revising material is crucial for sustained success.