There is little risk of committing a faux-pas or looking like a rude git when you're travelling in Australia. Manners, habits and attitudes to respect here are much the same as those at home.
It's not a myth, as you'll see when you're travelling in Australia, the general feel of the country is often very friendly and laid-back. Australians are very open and welcoming to visitors. The best way to make friends, is to talk about sport. Aussies are mad about watersports, Australian rules football, rugby and cricket. If you're a fan of any of these sports, you'll find it even easier to make friends.
Another way to meet the natives is to go to the parks where there are self-service barbecues. Everybody brings their own meat and drinks and is ready for a day of making new friends and sharing.
Generally, just follow the same rules of politness that you would back home. Add a touch of the carefree, relax and make "No worries!" your new watchword.
You're more likely to meet Aborigines in the centre of the country. They are the country's original inhabitants and their culture is considered to be one of the most ancient in the world. These days, the community lives mostly on the fringes of society and is ravaged by unemployment and alcoholism. Frankly, it's very hard to make contact with them. Most of them don't particularly like talking to tourists whom they believe to be disrespectful to their beliefs and traditions. I'm afraid that they're not wrong in this assertion. Be as respectful as possible. Don't try to photogrph them without asking for their permission and don't photograph their sacred sites (there are signs showing which areas are forbidden). Lastly, tourists love climbing Ayers Rock, the Aborigines' most sacred site, which they believe to be the navel of the world. So I don't need to tell you that they take a very dim view of this kind of activity, which they believe to be disrespectful. So remember your manners, don't climb the rock, just admire it from afar.