Hello student proper diet and sleep is very important for every student, student should take sound sleep of at least 8 hours a day.

If you study 6 to 7 hours a day with proper concentration consistently then you can easily score good marks in board examination.

To score 100 percent in board examination is little difficult if you didn't study throughout the year and in the end you start studying. But still you've a lot of time so start with a positive mind and prepare accordingly.

Feel free to comment if you've any doubt

Good luck