The essay paper in the Civil Services Exam conducted by UPSC carries 200 marks over 3 hours. Topics cover a wide range of social issues, women, politics, economy, science, and philosophy. Some important tips for the essay include choosing a topic you are prepared for, brainstorming and outlining points before writing, focusing on the issue, maintaining logic, writing between 1200-1500 words, and concluding with assessments but avoiding personal opinions. The exam evaluates understanding of the topic rather than factual information.