See - the preparation should start with checking syllabus. It is the same as class 12 so check the topics well. Segregate them into strong topics- the ones you are good at, weak topics that you need to work on. Revise the strong ones and build on the weak ones. Make a timetable to study them such that you complete them well in advance. Alongside, start practising on the questions at the end of the chapter as well as mock tests, previous year papers. 

All of this will require a dedicated and focussed approach. So start immediately and prepare well in hand for the entrance test. All the best.