Pronunciation is important to get a good score in the TOEFL speaking section, but the right pronunciation is not what students think. TOEFL test-takers quickly learn that the listening section is mostly a American accent. At this time, it is important to note the difference between 'accent' and 'pronunciation': an accent is the articulation common to a group of native language speakers, such as British accent or West coast North American accent; on the other hand, pronunciation is the articulation of a single individual when verbalizing a particular word in a language. All individuals speak languages, their own or a second language like English, with a certain accent and pronunciation. So how "good" does your pronunciation have to be for the TOEFL?
The speaking section of the TOEFL exam consists of six parts and each is graded according to the test-takers complexity (grammar, vocabulary), natural diction (like a native English speaker), and ability to accurately (completely and on topic) answer the questions asked by the examiner. These six parts can be divided further into use of present perfect, passive/active voice, pronunciation, intonation, annunciation, connection, description and so on. To stay on topic, what pronunciation is needed to get a high score for natural diction? Well, the answer is, "the one that is most similar to the English spoken in the region of the test-taker".
TOEFL exams are conducted and marked around the world. Usually, the accent of the marker are the same as where the test is being administered. For example, if a student is taking a test in western Canada then the accent of the examiner asking the questions and the one marking the answers will likely have been born in Canada, grew up in western Canada and has a N. American west coast English accent. So, for these TOEFL administrators it will be the easiest to mark and evaluate test-takers who learned and practiced English in their region. However, if this is not an option because the test is not in an English speaking country or the test-taker came from a different English speaking region then what?
Well, in this case most English speakers will agree that the easiest accents are west coast and east coast N. American English, then central N. American English, New Zealand, and most people, even other native English speakers find British English, Mid-south N. American English, and Australian English a bit tough to understand at times. Remember, the best way to be sure that you have the right pronunciation for the test is to practice and don't be shy! Copy the native speaker as close as possible no matter how funny it may sound to you. Even if the sounds seem strange at first, keep going, for the native speaker it is right way for the words to sound. So keep spitting those "th" and "ch" consonants.