I took IELTS (academic) a couple of years ago, so I'll just tell you how I prepared for it.
Reading: I took a course in my school specifically on IELTS. We read a lot of texts like the ones you find at the exam and made lots of exercises together. For this reason, my advice for you would be to practice as much as possible with texts taken from other exams, also by trying to keep track of how much time you need to do everything. Also, our teacher gave us some useful advice:
1) read the questions before starting to read the text
2) the true/false/not given are usually a paraphrasis of what is said in the text, so keep that in mind
3) usually "not given" is the right answer when it is not specifically said the contrary or it the content has not been explicitly confirmed
4) remember that answers/true or false are not about what you already know or about what you might infer from the text (not opinions, deductions etc) but only about what you can read there.
Speaking: see what are the most common topics in oral interviews and try to practice recording yourself or with a teacher/language partner. Even having spontaneous conversations with others can help, the important is that you speak as much as possible.
Writing: if you haven't already, you should see what sentences/words are normally used in essays written for IELTS, especially for what concerns diagram descriptions. Then, you should see some common topics and write about them as much as possible, trying to keep track of how much time it takes you. For example, in the days before the exam, I was writing one essay every day, and I think this really helped me in the end.