Even some days before the exam, you still can practice your listening skill. I personally recommend to listen again to the audio of your JLPT textbook and try to understand every thing that is said. Check with the script to see what you didn’t understand and why you didn’t understand it.
You can even make a dictation exercise. It is very useful to know exactly what you understand and what you don’t understand. When I just listen to the audio, I have the feeling that I understand the overall meaning and I move to the next track. But when I do a dictation exercise, I realize that there was a lot of little details I didn’t understand. Those details are not essential to answer the JLPT question correctly but working on the difficult parts is what makes you better.