Use English all the time
You may already be living and working in an English speaking environment. If you are not, committing to using English everyday may feel harder but it’s the only way to really improve your skills before the test.
Don’t see using English as something you do only when practising for the test in particular parts of your day. From the moment you wake up to the moment you go to sleep try to use English, even inside your head! You may need to explain your decision to family and friends so they are able to help you with your goal.
If you have decided a career move to an English-speaking environment is one you want to make, then putting 110% into your preparation will be worth it. Of course, once you are successful, you are going to be using English more frequently anyway so it’s good to start getting used to it now.