If you are weak in chemistry First you should try to clear your concepts You need to go through your text book throughly. You can take help of your teachers or friends to clear your doubts.

You can make your important notes at the time of study which will also help you at the time of revision.

You can also focus on the topics which carries more weightage in the exam. You can solve as many as MCQs for your practice.

Refer previous year papers to understand the level of the questions asked in the exam Join mock test series for your practice, After completing one chapter do revision again & note down your doubt to discuss with your teachers.

Be confident during your study.

Good Luck!