Hello aspirant, 

You can prepare for JEE MAINS through following books :

• For chemistry- Practice from NARENDRA AWASTHI, RC MUKHERJEE, and also follow NCERT as it is most basic and most important book. 
• For Physics-Prepare from HC VERMA and NCERT.
• For Maths-Prepare from RD SHARMA, and NCERT. 

You may also ask from your teachers as they know more than any one. 

Try to solve qualitative questions not quantitative because the most imporatant thing to get into iits is that you should have a clear concept and strong basic. 

Hope this would have helped you, if left with any query please comment. 

hey dear, that's good that you are thinking of preparing for iit's.12th class is a very good time to prepare for jee exam.So,dear make notes of your 12th notes as well as through some refrence books also like hc verma for physics specially for numerical problems and stay consistent over it,you will be able to clear jee in 1st attempt itself, if not keep trying with more study,all the best.