Hey Vikas.

First of all ,download last year entrance exam question papers of BHU BLAT from http://bhuonline.in/ and you can study from various entrance book for CLAT and ‘arihant' for BHU law exam is also there(you may go through it).

Apart from going through the normal stuff like General Awareness, English, Reasoning and elementary Maths, thoroughly go through the constitution specially rights and all, in a simple way learn constitution (atleast sections).

Now the main topic which you need to focus is

Mental Ability: This topic contains some reasoning questions and some basic maths till class 8th such as time and work, profit and loss , SI & CI etc.

Current Affairs and General Awareness: Read current affairs from June ‘17 to April ’18 and also do through study for general awareness type ques.

Verbal Ability: This section contains some reading comprehension and some grammar based question. Comprehension are easier one so any one can get through it.

Legal Aptitude : For this section you need to read some legal terminologies. Legal term are available on internet so will get it from there. Please read some popular articles also which is given in constitution of India.

Since you have more than one month to give the exam so be focused for that….

Hope this serves your query. Please feel free to respond and ask further questions.

All the best.