Follow the instructions. IELTS tells you what to do and when to do it then you just need to practice it.
Read the instructions carefully. Sometimes there is a specific requirement for your answer. Sometimes they say - No more than one word, No more than two words and or a Number and so on.
Pay attention to keywords. The key words give you the answer. If you focus on what you need then you wont panic about what you dont need like high level vocabulary.
Listening Test Don'ts:
Dont skip ahead. Use the time they give you to check your answers to look at your spelling and your logic. Dont overthink it. Dont outsmart IELTS. Do what they say.
In a paper-based test, dont write your listening answers on the answer sheet while you are listening. You are given time at the end to transfer your answers. This is another good reason to take the exam under test conditions as much as you can before test day.
Dont panic if you dont understand.The keywords and the answers are never vocabulary you dont know. They are not testing high level vocabulary. The vocabulary and answers you need will be intermediate to upper intermediate vocabulary. If you have prepared well then youll be fine.