Hello Shivangi,

If you have studied sincerely then you can easily prepare well for BHU LLB.

For effective study first of all, you should have the concentration power after that you can follow your timetable easily. Also keep in mind while you are making your timetable that it should not be hard to follow it. In starting, your timetable should be easy to follow, then gradually you can increase your study hours with concentration also. To study smartly, you should follow a proper routine of studing new chapters, solving numericals,and revision also in all the subjects. All three things should be the part of your preparation strategy in daily routine.
Your time table depends upon you and your situation like sleeping time, time for other home works or the time in which you are more comfortable for study i.e. quality time for you (in morning, in evening or in night). So, you should make your time table in your own way. In this way, you can prepare yourself well for the examination. Study hours should not be more than 12 hours, it's maximum. 
Thanks for query, you may visit again for further queries. 
All the best for your examination.

Hey.

For preparation of BHU LLB entrance exam for admission in 3 year LLB coursw You can use any all inclusive guide like Universal's guide to LLB and CLAT or Arihant's guide to BHU LLB. These guides  includes basics and practice questions for the topics of law entrances. UNIVERAL guide is used also for various other entrances. Other than that you can refer to previous year question papers  for a better guidance. For current affairs and verbal section the Hindu is considered as the best newspaper. You can use Word power made easy- Norman lewis for vocabulary. 

Best of luck!