HOW DO I UPGRADE MY SCHOOL GRADE?
According to your profile pic, it should be very easy.
Take a lot of notes even when bored ask teacher for assistance, always participant in class discussions even though you know it all than after school go straight home and do homework. If grades are really low like F's give teacher a xmas gift every xmas or buy them lunch sometimes maybe volunteer to do stuff around classroom.
Study more. Pass tests.
You should probably turn in homework on time, pay attention in class, study for tests, complete classwork, etc.