Introduction:
Incorporating previous years' question papers of UPSC Mathematics optional subject into your study schedule can be highly beneficial for your preparation. It helps you understand the exam pattern, identify important topics, and practice solving questions within a stipulated time frame. Here are some steps to incorporate previous years' question papers effectively.

Step 1: Collecting the question papers:
- Visit the official UPSC website or other reliable sources to download the previous years' question papers for the Mathematics optional subject.
- Ensure that you have question papers for at least the last 10 years or more, as it will give you a comprehensive coverage of the syllabus.

Step 2: Familiarization:
- Begin by familiarizing yourself with the question papers to understand the format, types of questions, and the level of difficulty.
- Analyze the weightage given to different topics and sub-topics within the Mathematics syllabus.
- Take note of any recurring themes or topics that frequently appear in the question papers.

Step 3: Creating a study plan:
- Allocate dedicated time slots in your study schedule to solve the previous years' question papers.
- Divide the available question papers into smaller sets based on topics or sub-topics.
- Decide on the frequency of solving the question papers, considering your overall study plan and the time available before the exam.

Step 4: Solving the question papers:
- Start solving the question papers based on the study plan you created.
- Set a timer to mimic the actual exam conditions and practice solving the questions within the allotted time.
- While solving the papers, try to identify any knowledge gaps or weak areas that need further attention.

Step 5: Analyzing the performance:
- After solving each question paper, thoroughly analyze your performance.
- Identify the questions you answered correctly, the ones you struggled with, and the topics in which you made mistakes.
- Review the solutions provided in the question papers and understand the correct approach to solve the questions.

Step 6: Revision and improvement:
- Focus on revising the topics in which you faced difficulties or made mistakes.
- Refer to standard textbooks, online resources, or consult subject experts to clarify your doubts and improve your understanding.
- Repeat the process of solving question papers and analyzing your performance to track your progress and identify areas that still require improvement.

Conclusion:
Incorporating previous years' question papers of UPSC Mathematics optional subject into your study schedule is an effective way to enhance your preparation. It helps you become familiar with the exam pattern, identify important topics, and practice solving questions within the time constraints. By following the steps mentioned above, you can make the most of the previous years' question papers and improve your chances of scoring well in the UPSC examination.