Familiarise yourself with all the different question types in the Listening and Reading Modules and possible question topics and tasks in the Writing and Speaking Modules of the IELTS Test.
For Speaking and Writing understand what the examiners are looking for. Familiarise yourself with the criteria for Writing - Task Response, Coherence and Cohesion, Lexical Resource and Grammatical Range and Accuracy. For Speaking understand what is required for Fluency and Coherence, Lexical Resource, Grammatical Range and Accuracy and Pronunciation.