no wuckas - this means no worries and is abhorrent. I say it in jest from time to time
yeah nah - apparently we share this with NZ. Most people will say "yeah", trail off, then say "nah" to start up the sentence again.
full on - often means "to assail one directly". eg "he came at me full on in the face". Or, can simply mean "totally" eg "we full on won that game". Alternatively, it can mean something that was really intense.
fuck off - refers to the scale of something, in terms of how intimidating it is. Like, "a big fuck off bag off lollies" or "she had some crazy fuck off tittehs"
mate - yes, we do say mate in this country. In my experience though, pretty much only men can pull off the mate. I said it on Friday night when this guy was asking me and my friends for some change and I think I did an okay job. It felt like a good way to let him down and make him go away, but seem kind at the same time. Saying mate is authoritative and reassuring, and lets the recipient know that your intentions are good.
g'day - almost in the same league as mate, but slightly less. I don't really know many people who use this term.
youse - plural form of you, typically used by "bogans" or the uneducated. I just saw it on facebook spelt like "use".
no worries - this is kinda like "you're welcome" or "sure". One often uses it to receive thanks
thongs - flip flops or jandals in NZ
fairo - Australians have a tendency to add an o on the end of words, like "righto" or "Tommo" or "Jacko". saying fairo is a less uptight way of saying "fair enough" and makes one feel slightly egyptian
trackies - trackpants. comfortable for lounging.
shit son! - expresses surprise or is a general exclamation. Also used by me in jest.
bogan - there are a few different types of bogans. They usually wear thongs with trackies, or ugg boots with leggings and talk about their pregnancy loudly on the train, whilst drinking some sort of bourbon and cola drink before 10am.
I should make it clear that nobody actually says "you flamin' galah" here!