Hi,
First of all you have to prepare a sound strategy for carcking this exam as no. of seats are very limited and fame of institute attracts so many candidates which makes it though. You need to get more information about it then prepare for it. I am provideing you the link of BHU LLB and Sample paper of BHU LLB go through them to get an idea about BHU LLB and prepare according to that. Best of luck!