There were originally three kinds of TOEFL tests: the Internet Based Test (iBT), the Computer Based Test (CBT), and the Paper Based Test (PBT). The CBT has been discontinued, and the iBT is fast replacing the PBT.
The iBT lasts for four hours and is divided into four sections: reading, listening, writing and speaking. Students are allowed to take notes during the iBT.
The reading task consists of three to five passages, and each passage has 12 to 14 questions, lasting for about 60 to 100 minutes. The listening section goes on for another 60 to 90 minutes, and students have to listen to six to nine passages, each containing about five to six questions. The speaking section is much shorter and the student is given six tasks, which need to be completed in less than 20 minutes. This is followed by the last section--writing, in which the student has to complete two tasks, lasting a total of 55 minutes.
The PBT is an hour shorter than the iBT, even though it tests all four skills. The listening section is 30 to 40 minutes and has three parts. The speaking section lasts 25 minutes, and students have to complete sentences and identify errors. Reading comprehension is slightly longer--55 minutes, while writing lasts only 30 minutes, where applicants have to write one essay in the 250 to 300 word range.
There are no hard-and-fast rules for success in TOEFL and, to a great extent, your score depends on your proficiency in the language. Like all tests, however, there are some general tips that you can use to prepare for the exam.
When studying, be sure to make use of mock tests. There is no dearth of resources that will help you practice for the test. You can find several sites that provide either complete tests or specific parts of it to help you practice. Apart from this, there are also several books available in bookstores that will be valuable guides for you.
Because the test is largely focused on English language skills, if you feel that your language skills are not up to the mark, you will need to either enroll into English teaching institutes, or find someone who will be able to teach you personally. There are several coaching centers, too, that can train you for TOEFL, which will include a section on improving your language skills.
Don't forget to time yourself during your practice sessions. Carry a watch with you to time each activity that you do. Do not be tempted to spend too much time on any section or task. Since the test is rather long, and there is quite a bit of writing involved, work on your stamina.