Some of my friends studied at JNTUH, and according to them you can work hard and follow some steps that will make you score better marks easily. Let me share some I got to know from them.
Getting good marks in JNTUH is a real task as the paper checking system in the university is a little faulty and requires considerable attention. In the end, the only thing that would matter is not your percentage but the skills you have acquired in the 4 long years of your academics. Try maintaining a 75% or above percentile and work hard.