When on board public transport, offer your seat to someone who needs it more than you. This includes people who are older, who have a disability or impaired mobility, who are pregnant or travelling with children.

Other things you can do to be considerate of others:

Threatening, offensive or unsafe behaviours are not tolerated and fines may apply.
https://transportnsw.info/travel-info/using-public-transport/travel-courtesy-etiquette

Under the NSW Public Health Act, anyone who enters Australia from another country will be subject to a 14-day self-isolation quarantine, with fines of up to $11,000 or six months’ prison if they do not comply.
Source:

https://www.theguardian.com/world/2020/mar/17/how-australia-will-enforce-coronavirus-self-isolation-rules-for-overseas-arrivals

Social distancing is an effective measure, but it is recognised that it cannot be practised in all situations and the aim is to generally reduce potential for transmission. Social distancing includes:

There is no need to bulk-buy products at supermarkets including toilet paper, paracetamol and canned food.

Retrieved 17 March, 2020
Read more on:
https://www.health.nsw.gov.au/Infectious/alerts/Pages/coronavirus-faqs.aspx

While indoor gatherings of fewer than 100 people are still allowed, the new guidelines say there needs to be at least four square metres available for every person in the area.
Remember: Be informed but don't panic.
Source:
https://www.abc.net.au/news/2020-03-20/coronavirus-covid-19-scott-morrison-enhanced-social-distancing/12075532
Retrieved 20 March, 2020

Source: 

https://preview.nsw.gov.au/covid-19/social-distancing