TOEFL is divided in four different modules which consists of the following:
Listening: This section involves listening to lectures, classroom discussions & conversations and answering questions. You must be alert and active in this part of the exam as the test progresses you need to answer questions based on what you have heard in the audio.
Reading: This section involves reading 3 or 4 passages from academic texts and answering questions. You can prepare for this part by practicing reading passages from books or papers. The passages in the test can be from anywhere. In this section, only reading ability of the candidate will be checked.
Speaking: In this section, you will have to express an opinion on a familiar topic, you will have to speak based on the reading and listening tasks. The candidate's understanding ability will be tested here. Basically, you must explain what you have read (an elaborated explanation is given in exam pattern page).
Writing: In this section, You will have to write essay responses based on reading and listening tasks. You will also have to support an opinion in writing. You should be well informed in-order to crack this section as knowledge on styles of essays and writing techniques play a vital role.