Tax help, page-8

First I think you need to start keeping a proper paper record of your buying and selling.
For each parcel of shares you buy, write down the company name, buy date and total cost.
When you sell that parcel write down the date and net return.
If bought and sold under 12 mths it is income (can't claim cap gain or loss).
If held for longer than 12 mths - a cap loss or profit - if profit can claim 50% discount.
No such thing as FIFO  LIFO. You decide which parcel you are selling.
Cap losses can be carried forward as long as you like - but there is a formula on how you apply them - google ATO and read up about it.

Print out all your buy and sell contracts and work out what you bought and sold each year.
The way to minimize your cap losses is to keep proper records and then you work out which parcel you are selling to minimize your cap loss.

Your 13/14 tax return should have been done by Oct last year unless done by an accountant/tax agent.

As suggested seek out an accountant. If you don't understand - do some research and learn more on the subject if you intend to trade/invest in shares.  Good Luck.