You will have to get hold of Australian broadcasts and tv programmes. They have a very different accent and quite a number of their own idioms. As always when hearing another language, the rhythm of the language needs to be learned in order to hear the words being spoken.
Here is a guide to the phonology: 12.1 Australian pronunciation
This gives a glossary [sometimes facetious!] Australian English Glossary from A to Zed - Travelogue