Dear Ms. Priya;
This is a good thing that you are studying 11part also. Use only recommended books and do not left any single part in a question  and not left a single question, by this your concept will be more clear. Do not study 50-50% by 2 books. first learn concept then only try to solve problem , do not jump in theory part.Try to get below books for IITJEE. 
Physics:
1. H.C.Verma
2.  NCERT Physics
3. B.P.Bhatnagar
4. Halliday-Resnick(any one book  from 1/4)

Chemistry:
1. NCERT Chemistry
2. I.L.Finar(Ref.)
3.  R.C.Mukherjee(Concept book)
4. R.N.Sarin
5. J.D.Lee [Ref.;selected parts]

Mathematics:
1.  TMH IIT Mathematics
2. M.L.Khanna(only for some chapter)
3. I.A.Maron(Ref.)
4. A.Dasgupta
Please feel free to post as many doubts on our discussion forum as you can.
If you find any question Difficult to understand - post it here and we will get you the answer and detailed 
solution very  quickly.
We are all IITians and here to help you in your IIT JEE  & AIEEE preparation.

All the best.
 
Regards,
Askiitians Experts
Pramod Kumar
IITR Alumni