Dear Mohit,It is great course to pursue.

In order of preparation you should keep these points-

1.You need to be more specific to the entrance exam you want to prepare.

2.every university has different criteria and exam pattern.

3.clear your concept of topics you have read in bachleors degree as well as read basics of forensic science.

4.read some GK questions as well.

5.Focus on previous year question papers

Top university which provide this course are  National Institute of Criminology and Forensic Science ,Delhi  and Osamania University etc. 

Hope this helps.