It's not just the language, it's also the accent. But knowing uniquely Australian words and phrases is an important first step in understanding the Australian language.
Don't get into a blue. Know a bit of Strine and you'll be fine. In a pub you could get asked to shout. Don't holler your head off. You're just being reminded it's your turn to pay for the next round of drinks. If you're visiting Australia and are non-Australian but you do speak English, you should have no real problem understanding the local lingo.
Let's say you’re an American male on a visit to Australia and you meet this dinki-di Aussie sheila. You click, and she wonders if you can meet her later, say at 5pm, near the lifts by the chemist’s on the first floor of the Oz Building. "No worries, mate," you say, having already picked up that Aussie expression.
To better understand the Australian languge, know some common Australian words and phrases. While some of them may be colloquial in usage, they are commonly used in spoken or written Australian. They are neither Aussie slang, nor the more esoteric rhyming slang, although the distinctions are too fine to worry about.
They say Australian rhyming slang comes from cockney and was brought to Australia by the convicts who first settled the country. They used rhyming slang if they didn’t want others, particularly the authorities, to understand what they were talking about. It may take time getting used to, but if you do hear it, you can always ask what it means.
A common variation of rhyming slang is to drop the rhyming word altogether. So you could simply "ava captains" (have a look) instead of "ava Captain Cook" where "Cook" rhymes with "look." Sometimes when the rhyming word is dropped, the remaining word takes on a plural form ... to confuse you further perhaps.
As with normal slang (who said slang was normal?), usage changes with time and many rhyming slang words and phrases in the past may no longer be in use. But for whatever it's worth, here are a few rhyming slang examples, if only to understand how rhyming slang words and phrases came about.