Reviewing the solutions of previous year papers can indeed be helpful in refining one's approach to incorporating international administrative trends, best practices, and case studies into answers for Public Administration. Let us delve into the details of how this can be achieved:

1. Understanding International Administrative Trends:
- By reviewing the solutions of previous year papers, candidates can gain insights into the types of questions that have been asked in the past related to international administrative trends.
- They can examine the solutions provided to understand the key concepts, theories, and frameworks that have been used to address these questions.
- This process allows candidates to identify the recurring themes and trends in international administration and develop a better understanding of the subject matter.

2. Incorporating Best Practices:
- Previous year papers often provide solutions that showcase best practices in the field of public administration.
- By carefully studying these solutions, candidates can learn how to incorporate these best practices into their own answers.
- They can identify the strategies, policies, and approaches that have been successful in addressing various administrative challenges.
- This enables candidates to enhance the quality of their answers by including relevant and effective best practices in their responses.

3. Analyzing Case Studies:
- Many previous year papers include questions that require candidates to analyze case studies related to public administration.
- By reviewing the solutions to these questions, candidates can learn how to approach and analyze case studies effectively.
- They can understand the key factors to consider, the frameworks to apply, and the methodologies to use when examining and discussing case studies.
- This helps candidates to develop their analytical and problem-solving skills, enabling them to incorporate relevant case studies into their answers and provide well-rounded responses.

Conclusion:
Reviewing the solutions of previous year papers is an invaluable exercise for candidates preparing for the Public Administration exam. It not only helps in understanding international administrative trends, but also in incorporating best practices and analyzing case studies effectively. By utilizing this approach, candidates can refine their answers, demonstrate a comprehensive understanding of the subject, and increase their chances of success in the UPSC examination.