Societies of editors/writers' centres

Canberra Society of Editors
Society of Editors (NSW)
Society of Editors (Queensland)
Society of Editors (South Australia)
Society of Editors (Tasmania)
Society of Editors (Victoria)
Society of Editors (Western Australia)

New South Wales Writers’ Centre

The Australia Society of Authors has a link to all writers' centres on its website.

If you want to be a great writer I recommend you read the works of great writers. These award winners are a good place to start.

Australian awards

Children's Book of the Year Awards
Commonwealth Writers’ Prize
Prime Minister's Literary Awards
National Youth Week Awards (Australia)
NSW Premier's Literary Awards
The Victorian Premiers Literary Awards

Science fiction

Hugo and Nebula winners for published fiction
Aurealis awards (Australian science fiction, fantasy and horror writers)

International awards

The Nobel Prize in Literature
The Man Booker Prize
Pulitzer Prize

This is by no means a comprehensive list. An excellent resource published by Thorpe-Bowker is Australian Literary Awards and Fellowships. You can also see a general list on Wikipedia.