One good newspaper like The Hindu or Indian Express- Make notes in GS 1, 2, 3 And 4 format like the way the mains syllabus is organised. For each subject see the syllabus and previous year question papers. Supplement each subject with the help of newspaper content.
History– Ancient:: 6th NCERT+TAMIL Nadu board +1 book
Medieval:: 7th NCERT+TN board +1 book
Modern::12th NCERT + Bipin Chandra’s Struggle for Independence or Spectrum book
World History:: NCERT 9th,10th, +1, +2
Art & culture:: +1 NCERT +selected chapters from Nitin Singhania
International Relations ::The Hindu + one good monthly magazine to supplement the your notes.
Economics:: NCERT 9th,+1 , +2(Macroeconomics)
Environment::NCERTS + Newspaper
Science:: Inventions that were in Newspaper.