In case you are not confident about your preparation then you can take a professional guidance for it.

Some of the recommended books for UPSC you can consider are:

NCERT (XI) Ancient India- R.S. Sharma

NCERT (XI) Medieval India- Satish Chandra

NCERT (XII) Modern India- Bipin Chandra

Freedom Struggle- Bipin Chandra

Modern India- B.L. Grover

Physical and Human geography by GC Leong

Hope this helps you.

Good Luck.