In last days of your preparation you should focus on the topics which carries more weightage in the exam. 

Try to understand the fundamentals to solve all the questions without facing much problem. 

You should write down all the important formulas and shortcuts. Give as many as mock test series for your practice to analyse your preparation level at regular interval of time. You should be aware of your strength and weakness. So, that you can work upon them. 

Refer previous year papers to understand the exam pattern and level of the questions asked in the exam.

All the best!!