1. Do not talk during the class .
2. Make notes .
3. Drink water in between class as drinking water gives oxgyen to your brain which will ultimately gives attention in class
4.in breaks walk and do physical movement because physical movements also make brain attentive.
5. Don't hesitate to ask questions during the class .
6. And finally try to have control over day dreaming
To an extent, do what makes you happy. Don’t pick subjects you feel you have to take, take subjects you want to take and that your interested in. Don’t choose it because a friend is doing it or it’s the popular choice, doing because you have decided to do it.