For the essay paper in the UPSC mains, candidates should focus on clarity, coherence, and originality of thought. It’s crucial to organize essays with a clear introduction, body, and conclusion while presenting balanced arguments. Incorporating relevant examples, quotes, and case studies can greatly enhance the essay's depth. Understanding the topic's nuances, including various perspectives, will demonstrate analytical abilities. Practicing essay writing regularly aids candidates in managing time effectively during the exam. Finally, focusing on improving language and expression ensures that the essay is not only informative but also engaging for the examiner.