Hello dear student !
In order to prepare for BHU pet entrance exam for MSc in Botany , first of all you have to make sure that you downloaded the syllabus and so many previous year's question papers. Just be regular and consistent with your studies. Revise regularly and prefer some good notes for it or the one which you have made while preparing. Study smartly and focus on the topics which are repeatedly asked in the previous year's question papers. Relax and eat healthy and take proper sleep , it is very important for all the exams.
Hope this will help you