Introduction:
Maintaining a balance between solving previous years' papers and studying new concepts is crucial for effective preparation of the Civil Engineering optional subject for the UPSC exam. By following a strategic approach, candidates can ensure comprehensive coverage of the syllabus while also practicing exam-oriented questions.

1. Understand the Syllabus:
Start by thoroughly understanding the syllabus of the Civil Engineering optional subject. This will help in identifying the important topics and allocating time accordingly.

2. Create a Study Schedule:
Design a study schedule that allocates specific time slots for both solving previous years' papers and studying new concepts. This will ensure a balanced approach and prevent neglecting any important aspect of the subject.

3. Prioritize New Concepts:
Give priority to studying new concepts initially. Allocate more time to understand and master these topics. This will build a strong foundation and make it easier to solve previous years' papers later.

4. Solve Previous Years' Papers:
After gaining a solid understanding of the new concepts, start solving previous years' papers. This will help in familiarizing oneself with the exam pattern, time management, and the type of questions asked.

5. Analyze Performance:
After solving each previous year's paper, analyze your performance. Identify the areas where you faced difficulties and revise those concepts again. This will help in strengthening weak areas and improving overall performance.

6. Revision:
Regularly revise both the new concepts and the solved previous years' papers. This will reinforce the understanding of the subject and improve retention. Focus on key formulas, concepts, and problem-solving techniques.

7. Mock Tests:
In addition to solving previous years' papers, attempt mock tests specifically designed for the Civil Engineering optional subject. These tests simulate the actual exam environment and help in assessing your preparation level.

8. Time Management:
Manage your time effectively while studying new concepts and solving previous years' papers. Allocate fixed time slots for each activity and stick to the schedule. This will ensure a balanced approach and prevent procrastination.

Conclusion:
Maintaining a balance between solving previous years' papers and studying new concepts is essential for the Civil Engineering optional subject. By following a well-planned study schedule, prioritizing new concepts, regular revision, and analyzing performance, candidates can achieve comprehensive preparation and increase their chances of success in the UPSC exam.