I'm surprised some of the Aussies haven't added a few...
Cobber - mate, friend
Arvo - Afternoon
Garbie/Garbies - garbage men/women
Firey/Firies - fire fighters
Footie - this can mean... Rugby (meaning Rugby Union), League (meaning Rubgy League - a different version of the same game) , Aussie Rules Foot Ball (very different to the American version...), Soccer or even American Football
Ambos - Ambulance men/women, paramedics
Pom/Pommy - English person (often rendered as ...pommy bastard...)
Servo - Gas Station
Servo pie - meat pie bought at a servo (not usually a culinary delight)
Bottle-o - Off licence/beer shop
Strides - trousers/pants
Bubbler - NSW (maybe otherplaces too) for drinking fountain
Snag/Snags - Sausages usually cooked on a barby (BBQ)
Bewdy/Bottler/Ripper - terrific
Dunny - a rest room to Americans
Hoon - Hooligan
Seven Course Meal - 6-pack of beer and a meat pie
Troppo - if someone's gone Troppo they've gone Bananas
Hard Yakka - Hard work
Kangaroo loose in the top paddock - referring to someone with a screw loose in their head/bonkers
Bogun - nearest US to this would be using Red Neck as derogatory term
Fun fact. When Tony Abbot was Aussie Prime Minister a guy was arrested for shouting out "Oi, Abbot you effin' bogun". Lots of letters in our local paper defending the guy who was arrested (Abbot was our member of parliament and most people in the area agreed with this in-depth analysis of his character; although Pommy Bastard would have been a more appropriate description....)
Ten Pound Pom - someone who emigrated to Australia in the 1950's or 60's when the Aussies offered assisted passage (at £10...) for people in listed occupations. (Tony Abbot's family were £10 Poms)
Moving away from slang...
Numbers can be different too...
Twenny, Thirdy (30), Fordy (40), etc.
Place names can be tricky, similar to British place names the pronunciation is sometimes not obvious (but often different to how a British English speaker would say it); yup, Aussies can get English place names wrong just like Americans
... e.g. Wagga Wagga (yes, it is a town) is pronounced Wogga Wogga)
There a lots more and they often differ between states or across states.