'Yes'. One year preparation is enough but in that one year give your best. This exam need a positive mindset and dedication. During that one year you would have to cover
1. Last two years Current Affairs (You can refer online sites such as UPSC Panda
, Clearias etc.)
2. All NCERTs and Standard Books (Keeping syllabus in mind)
3. Improve writing skills (Write at least 2-3 answers daily)
4. Previous Year Papers ( Find out the important topics)
5. Economic Survey, Budget and India Year Book, one year Yojana Magazine.
All the best!