Travel is your best choice. It can inspire you in some ways and learn many things that you can't learn in books. As for the location, mountains and rivers are your first choice, such as Qingdao and Dalian. I'm from the northeast, and I only know that these two places are good. Cultural relics are also good, and so is Beijing. If you like big cities, you can go to Shanghai and Hong Kong. If the economy permits, you can go to Tokyo, and further, you can go to new york.

At home, you can also make a plan for yourself, such as memorizing a certain number of English words at a certain time every day, keeping a diary, reading idioms, reciting ancient poems and so on to enrich your home life.

You can attend one or two cram schools, but not too many. It's no use.

13 years old is the age to develop intelligence. You can get in touch with what you are interested in and then explore, which will make you smarter.