Good preparation does not depend upon how much hours you study. It depends upon the efficiancy & quality of time. You should not calculate the time for you study but study efficiently whenever you study.

In order to crack the exam here are some preparation tips you can follow:

Go through with the previous year papers to take an Idea about the exam.

Your basic should be clear of class 12th for the particular subject in which you are going to pursue B.Sc programme.

Good Luck!