Study concepts and write it briefly in your notes. Refer NCERT syllabus as they are good enough to secure some expertise in these three subjects. Practice more and more. Start today rather to think for tomorrow. Short time is enough if you have keen determination.

Best of luck.

well, all I can say is to give your 100% in every subject. practice past years papers as much as you can. you should be thorough with the NCERT syllabus in all the three subjects. Be positive and consistent during your preparation.

All the best!