This actually depends on your current level. First of all, TOEFL needs a vocabulary of 8000- 10000 (especially important in reading). Do you have it now? If it is not enough, it needs to be strengthened. Second, listen, don't think about going to see any American documentaries or anything. It's not that it's useless, but that you only have three months, and you have less study time. After watching a movie, you do nothing for a day. It is impossible to make a big improvement in this way.

The best way for you to improve your listening now is to do more listening questions and insist on doing, listening and answering. Each TOEFL composition takes about 3 minutes. Spend an hour or so practicing listening every day. Practice reading for about an hour. Of course, if you have a foreign friend, bring him to speak English. (but not the most important).

The two most important parts of TOEFL are listening and reading. Not only listening and reading needs, but also writing and speaking will test your ability in these two parts.

Writing this kind of thing can't get better soon, just remember to stick to the theme and write your meaning in the simplest words (grammatically correct). Actually, it's the same (it's difficult to practice oral English in China unless you spend money on foreign teachers).

Of course, the above is only recommended by ordinary college students. If you want to go to a prestigious school like Harvard. Then the requirements are different. I don't know what you think.