Hi Aspirant, you can prepare for exam from anywhere. First start with previous year papers. As there are many sections are there in the paper, just check the pattern that from which topic they are asking maximum number of questions. How much weightage is given to which topic in every subject. Based on that choose the topics and start the preparation.

For physics you can put more focus on 11th and 12th NCERT books.

For mathematics ans aptitude related topics R.S.Agrawal.

For IT related questions you can generalise topic from oreviois year papers and try to reas from google instead of any book.

For mathematics and physics try to find out the shortcuts to answer questions. So that you can save your time. For aptitude you can refer R.S.Agrawal. Try to solve as maximum as mock tests so that you can practice more and know time management for the exam. 

All the best for preparation and exam.