Hey.

As per the pattern of BHU LLb there are 150 questions with 450 marks from the topics of English Comprehension, General Awareness and Current Affairs, Aptitude and Mental ability and Common legal knowledge.3 marks for correct answer, 1 deducted for wrong and zero for unattempted.

For preparation You can use an all inclusive guide like Universal's guide to LLB and CLAT which includes basics and practice questions for all these topics which can also be used for other similar entrances. You can also use Arihant's guide to BHU LLb. Other than that you can refer to previous year question papers for each entrance for a better guidance. For current affairs and verbal section the Hindu is considered as the best newspaper. You can use R.S aggarwal'a books for Logical Reasoning or quantitative section in case you need a separate book other than universal's guide. You won't require a separate book for reasoning as the level isn't that high. Univeral/arihant woukd be fine.  Make sure you practice a lot using previous years question 

Best of luck