For me, when I used to do listening exams in French and German at school and university, I used to write everything I heard! I really found it difficult to try to read the questions, listen and write the specific answers all at the same time. In IELTS you are lucky in that you have some time before listening to read the questions, underline the key words and try to predict the kind of language you might be listening for, including synonyms of the words in the questions. Then, you have to listen and if you can of course answer the questions as you listen, then do that - you have 10 minutes to transfer your answers to the answer sheet at the end. However, if you do not hear what you think you should be listening for, then write down anything else you hear that you think might be important - you never know, that might be the answer.
You can write whatever you like on the question paper so use it - underline the key words, write the synonyms, write your predicted answers and also, write everything you hear! For me sometimes, I could not follow the listening at all and so I simply noted down the few words that I understood. Often, when I came to transfer my answers to the answer sheet, I realised that those notes contained the answers.