Hi, your problems with TSE are unfortunate and you are not alone. It is very difficult to obtain a perfect score mainly because there are no books to practice from. But if you live in Toronto, the TDSB (
[link] has a pronunciation class at the Bickford Centre (777 Bloor West) four days a week from 3:30 to 5:30. This would give you some practice. As for the strategies the TOEFL.org has some sample questions which may or may not help. Pronunciation may or may not be your problem. In my experience, the biggest problem is getting your thoughts organized fast for each question and that can be done only with practice.