Hipopp the ATO accesses someone if they are to be classified as...

Hipopp the ATO accesses someone if they are to be classified as a trader or investor from their trading activities. You cannot deem yourself to be one or the other. Your trading/investing style does.

Capital gains tax only needs to be paid on a realized profit. Realized meaning the position or part of has been closed.

You won't be able to avoid tax other then closing a position at a loss regardless of how long you hold the stock.

Distinguishing between being a investor and trader can be a grey area. If your someone who typically holds stock for long periods of time(12 mths or more) then your a investor. If your someone who holds stock short periods of time, has a high turnover and basically carry's your activities on like a business then your a trader.

As an investor the biggest advantage is getting the 50% CGT discount if your holding was closed after 12mths. For example if you made $10000 on BHP and held the stock for 13mths, only 50% of the profit($5000) is taxed at your marginal rate.

If you sell your holding before 12 mths, regardless if your a investor or trader your whole $10000 profit will be taxed at your marginal rate.