Candidates can improve their essay writing skills for the UPSC exam by following specific strategies. First, understanding the essay format is crucial, with an emphasis on clear structure and coherent arguments. Practicing writing essays on various topics enhances fluency and adaptability. Reading diverse essay papers, along with feedback from mentors, provides insights into quality writing. Furthermore, developing a rich vocabulary and clear expression makes essays engaging. Lastly, time management during practice ensures that candidates can complete essays within the stipulated time during the actual examination.