If you know that you have homework for the class, get a jump on it and get it done before you even get home.  If there is no homework for the class you’re in, do homework for another class. Don’t assume that you will have time in class to do homework that is due the same day.  Instead, use the time to get ahead on work that is due the next day or later. Try coming up with and implementing an organizational system for yourself.  Get colorful pens and highlighters and write down important deadlines and events in your calendar or agenda. Make a list of all the things you need or want to do once you leave class.  This will help you become organized and prioritize the items you need to do as well as give you a productive activity to do while you are still in class. If you have an upcoming event, such as a party, write down a plan for it.  Think about things you will need to buy, decoration ideas, and a guest list.  Write down all of your ideas so that you won’t forget them. If you have reading to do for another class or for pleasure, tune out your teacher and read.  Hide the book inside the class textbook, particularly if it is a novel or a smaller textbook. Try to remember to look up occasionally so that the teacher thinks you are paying attention to her. If you get caught, apologize.  However, know that it is better to get caught reading than doing less productive things and you are less likely to get in trouble.

TL;DR in Chinese:
写这门课或其他科目的作业。 制定精细的统筹计划。 列一份待办事项清单。 筹划即将到来的活动。 上课时安静地看书。