For General studies you can go for the following books:-

India Struggle for Independence by Bipin Chandra; NCERT Books ( XI & XII )

General Studies mannual--by Tata Mc Graw Hill

General mannual--by Spectrum

Everlatest general knowledge- by O.P.Khanna

G.K. Refreshers- by O.P. Khanna

You  should refer to newspapers and magazines like Civil service Chronicle, Pratiyogita Darpan, Competition Success Review etc.