if you want achieve 85 % then you should make your strategy regarding your weak subjects so that you can tackle them smartly for this purpose firstly make friendly time table which can provide you regularity as well as consistency after that you should revise those portion repeatedly which will be important for your syllabus and also you can apply on your weak subject so that you can gain more knowledge and self confidence.
- - Revision.
- focus on your doubt clearance with the help of your school teacher or tuition teacher.
- More practice of your chapter exercise and any reference book questions Exercise.
- Take self test with integrated mind.
- join any test series regarding your board which will provide you experience and also boost your speed (Time Managements)