How long were you in Australia for? Australians (I am one of them) have a very particular accent and use a lot of slang which takes some time to get used to. Also were you able to speak to the locals while you were there or mostly international tourists? As that would make a huge difference. Also, when you speak to native English speakers, make them aware that you want to learn the language, and that you want them to correct your English. I hope that helps.

Me too