First of all, focus more on math and English and less on other subjects. Then, study math and English as hard as possible in other subjects, followed by the most common preview. This is really important. I had written all the exercises in the textbook when I was preparing for math. When preparing for English, I remember the words while reading them, and then look at the text to find the key points. Grammar should also be memorized. You can also ask more questions about math and English in class.