The syllabus of the entrance exam is as same as you have studied in class 11 and 12. So the books that you have had in class 11 and 12, prepare from those books. NCERT Textbooks are great for preparation. Along with this, polish your general knowledge and be aware of all the current affairs. Practice some aptitude and reasoning. Solve previous year exam papers and give mock tests. Instead of choosing a random topic from the syllabus, you must break the syllabus into sub topics and then start preparation for the exam.