From my experience:
0. Take some couching courses for IELTS (nothing else, not Business English, no nothing, only IELTS)
1. Take IELTS mock test - it will show you your weak points.
2. Take some couching courses for IELTS (nothing else, not Business English, no nothing, only IELTS) focusing on your weak points.
In some countries couching courses for IELTS are done in local language, not English. In my personal opinion in that case you are better off doing it yourself.
Preparation for IELTS DIY:
For Listening - LISTEN to BBC radio, audio-books (with British English) avoid watching movies. You need LISTENING, not WATCHING. (I got - 8, missed one of the parts)
For Reading - read, read and read. Anything you find. For True/False/Not Gven questions (many find them most difficult) - change question into negative, if it matches then your answer is No, If doesn't match anything then - Not Given. (I got - 9, I like reading)
For Writing - read, read and read books on IELTS Writing. It is not exactly the same as everyday or any other writing. And then write, write and write with your HAND. Typing is not the same as handwriting. (I got - 6, because I wrote using simple vocabulary and did not mention opposite point of view)
For Speaking - practice making a speech about a subject, to gain confidence. Do it with a native speaker and watch their reaction. Brush up your accent in a way people do not have a problem understanding you. (I got - 7.5, I am still not sure why not 8)
The day before the test - go to bed well early, to make sure you slept enough to have fresh brains. This is very important. As important as your whole preparation process for the test.