Hi,
I studied French for my HSC and I have to agree listening was perhaps the most difficult skill. It is definitely advised that you try to immerse yourself in the French language in order to become familiar with the listening to French words. You might try watching French tv shows/movies and listening to French music. Listening to French news (available on the SBS website or websites like
www.lemonde.fr can be really helpful
The main struggle I had was that I did not understand much of what they were saying, seeing as how fast they talked. The French HSC listening texts are definitely slower than an average French speaker. I suggest listening to a free podcast called 'News in Slow French' to try to become used to listening to French at a slower pace, then eventually moving to faster-paced listening.
Hope I helped! If anyone has any questions about French, please message me.