Common mistakes made by candidates in the UPSC Mains Examination often include inadequate preparation for the essay paper and poor answer presentation. Many candidates either underestimate the importance of practice writing or fail to structure their answers effectively. Additionally, overlooking the relevance of current affairs can lead to subpar responses in general studies papers. It's also common for candidates to exceed word limits, resulting in crucial information being missed. Lastly, candidates may neglect to analyze the questions thoroughly, affecting the overall quality of their responses. Awareness of these pitfalls can enhance performance.