volunteer
As long as you are 16 years old, you can call your local volunteer organization online for details. I think this is a very meaningful thing.
Attend a training class
You can take part in training courses you are interested in, such as calligraphy and English training.
Do textual research
Get a driver's license, or a tour guide card, an English certificate or something. If you have time now, read a good book and you will definitely pass it.
Apply for a job
Looking for a job depends on what kind of job you personally like.
Find friends to come out to play.
Usually play ball games, come out for supper at night, and if you have money, you can travel with some friends.
play games
Play some games that you don't have time to play at school. But play moderately and don't be too addicted.