The above reference will provide most of the information you require.
They show how the provisions of the Income Tax Assessment Act apply to share trading and are based on decisions of the High Court.
My personal view is that you do not need ABNs or business plans. Your objective in buying and selling shares has to be for making a profit - anything else is nonsensical.
Having said that it is easy to put together a "business plan" in hindsight. The key is your trading - if you buy and sell shares with a view to making a profit, that should be clear in your trading. If however you also buy shares for "investment" that should also be clear and you can put these under "investment" activity as opposed to "share trading".
Have a look at the reference and you are welcome to raise any other issues.
I suggest you do all the work and have a quick chat with an accountant. Then you can prepare the return yourself or have the first one prepared by your accountant and future ones yourself.
