So you talked about the 8/8/8-hour thing (8hrs studying,8hrs sleep,8hrs other activities) The thing is I have class for most of the day, after school I can't really make 8 hrs for studying and 8 hrs for family.

Thanks for the question. 

Ok then in this case, you can allocate at least 2 hours daily for your study time.Some people get more out of studying at night while others find the best time to study to be the morning. Find out which is your good time to study. It’s hard to focus in class for all 8 hours .Why don’t you try reading or recalling the topic covered by the teacher immediately after class. This helps a lot in terms of understanding better and also remembering better. And then try writing down one or two points that you understood .Once you go home, it is good to revise what you were taught in the morning. This helps to get a clear idea of the topic and if you find any doubts, you could clarify the next day.Doing this on a regular basis has many benefits like you will be interested to attend the classes regularly, make notes, and understand the subject better. Further, you will not need to worry about the exams at the last moment as you will be prepared well due to this study.