The first thing to do is to find out what module of IELTS are you going to take, Academic or General Training. Usually Academic module is intended for future students and the General training for immigrants, but you should not assume – check and double-check which one you need to take.
The difference between two IELTS modules is that Reading and Writing tests are different in Academic and General. The Listening and the Speaking tests are the same.
The difference in Reading test is that you may have to read 3 longer and more complicated passages in Academic versus 4 smaller and easier texts in General Training.
From my experience, the fact that I studied for Academic reading and practiced on Academic kind of texts didn’t heart me and even helped me. The problem was the Writing test assignments. The difference between Academic and General Writing test is that in Academic you receive a graph and the task is to describe it in 150 words. In General Training you receive a description of a real-life situation and the task is to write a letter about that situation.
So I learned my lesson and now my advice to you is: