The best strategy to prepare for the IELTS exam is to introduce oneself to as many resources written and spoken by native English speakers as you can. Watch English-language film and TV, and study magazines, newspaper, and literature. Your ability to communicate with English in a range of registers and conditions will be tested on the exam, so the more context-specific your comprehension of English, the better. As much as you can, practise speaking, even if it's just to yourself in front of a mirror.