Hi Miakyou..
Actually the listening topics differ amongst the test takers even if they are taking the test in the same period. The topics might be the same but the details and the subject inside the topic most likely will be different from one person to another. But since I took 6 TOEFL test (2 official and 4 non-officials) here is a list of the subjects that you will likely encounter:
1. Psychology
2. Biology
3. Archeology
4. Geology
And there is more, but sorry only those I can remember for now. But I can give u some important tips for the TOEFL test. These tips helped me alot and might help u and the others as well:
1. Always Skip the Directions section (by clicking dismiss directions) to save some time.
2. don't worry about the time in Listening and Reading sections, take as much time as u want in those two particular sections, but monitor the time very carefully in the Structure/Writing sections, because u will be needing every second available in these 2 sections.
3. in the short listening dialogues concentrate on what the last person says, because 80% chance you will be asked about what he ( implied, stated, assumed ) and be careful from the assumed part,
4. in the long listening dialogues make sure you understand the main idea because most likely you will be asked about what they are talking about, and try to memorize the small details as much as possible, don't panic if u didn't understand a meaning of the word just carry on as the narrator speaks, (if it helps, close your eyes so that you have a better concentration and vision on what they are saying)
5. Another thing that I've noticed in the long listening dialogues is, the first question will most likely be answered during the beginning of the dialogue, the second might be in the middle and the last question is answered towards the end of the dialogue.
6. as for the structure section, I only have one piece of advice, and it might not help you very much as you may already know it.. If u couldn't make a choice Just eliminate the choices that you think are wrong and compare the tones between the remaining choices.. ofcourse in a period of time no longer than 45 secs for each question.
7. in the reading section, focus on the first paragraph , and the first sentence of the following paragraphs, and since u have enough time u can read the whole passage thoroughly not worrying about the time.
8. in the essay writing section, its important to take 2 minutes to put up some thoughts and ideas about the topic, its good and better to express and discuss examples from your life (you can lie as much as u want) to support your statements, if you don't know a spelling of a word just don't type it, make your sentences simple and grammatically correct, because this is mainly what it matters, in each paragraph you must have atleast 3 sentences,
9. leave 5 spaces in the beginning of each paragraph, press enter twice after each paragraph, you can quickly set up your introduction paragraph from the main topic itself
10. Leave atleast 3 minutes to go through the whole essay, check for errors and misspelled words, because you will surely discover some,
11. Last thing, I'm not a teacher or anything, just a 17 years old student who had few TOEFL exams and gained some experience from it. And please excuse my bad English
and please don't hesitate to ask me about anything in the TOEFL test, I'll be here doing my best to help you guys =)