One of my cousins studied at IIT BHU, so I might be able to help you with the question. Here I'm mentioning some major key pointers which you should follow.

• Attend the classes regularly and take class notes.
• Do not miss Mechanical Workshops, Engineering Drawing classes. ED classes are a bit challenging but you have to be there strictly on time.
• Drawing sheets would be submitted and graded on every turn. Try to keep your drawings tidy. You can of course take the help of your classmates.
• For semesters buy previous year's question papers. Practice solved examples of ND Bhatt's book.
• If you are kinda new to programming, do not panic and start early. Questions in the exam would be of a decent standard. Chemistry, Physics, etc are the easiest ones.

Recommended Booklist:

1. Mathematics (Gorakh Prasad+Pondy Baba's Xerox)
2. Thermodynamics (PKNag); Engineering Mechanics(Shames).

The curriculum has been updated. These pointers will surely help you to secure a higher GPA and may pave the way to branch change.