To score good marks in BITSAT it is very important that your basics should be clear. 

You should learn all the formulas and equations if you want you can also make your notes to remember. Almost, your papers will be based on formulas. 

You can refer previous year papers to know the exam pattern and type of questions. 

Most important thing in BITSAT is time management. You should give mock test daily to work on your time management and to increse your speed. It will help you to solve bonus questions as well. 

Apart, from NCERT book you can also refer to Arihant publication for BITSAT.

All the Best!!