Bet (not involving money but something better) on each other who will get a high score in exams, test and other activities, this drive you and your friends to do their best. Make a deal with your parents (if possible) like you can get something out of studying hard, do it for long time, surely your mind will adjust and even without a deal, you will still review and study as hard as you did before. Try to set goals, or just challenge yourself by expecting to get this grade at the end, rewards can be a drive for you in study as well.