History: Most of junior high school history only needs to be memorized, and then the questions are done, so even if you don't need to work hard, you can make great progress by taking the time to recite.
Mathematics: There is no good way to improve mathematics. Improve the fastest with questions. It doesn't matter if you find your own weaknesses, even if there are many. One by one, as long as we can persist, we will certainly make progress. (I brushed three math teaching AIDS in senior three)
Physics: It's the same as math, but it's better to sum it up in time. This abstract thing depends on understanding.
English Chemistry: There are some similarities between these two courses, that is, memorizing, but unlike history, the emphasis is on understanding, and memorizing may not necessarily be a problem, so it is best to do a lot of exercises when memorizing knowledge points.
Chinese, I think the loss of Chinese points now lies in reading and composition, right? Buy a reading exercise, two a day, and recite the answers in time, because most reading answers are similar. Try to take time to read some good compositions, learn their ideas and language, memorize good words and use them directly when writing.
In fact, as long as you are willing to spend most of your time studying, it is no problem to improve. Besides, I'm talking about after-school exercises. The point is still in the classroom. The teacher doesn't understand the class, so it's no use doing more questions.