I live in Adelaide and yes the majority of Covid clusters in Australia have been quickly and decisively acted upon, but we have been fortunate that the numbers have never been 'high' relative to other parts of the world.
We've been dealing with cases in the 10's and 20's and very occasionally low 100's.
Australia introduced an effective contact tracing system very early and added a functioning app soon after, but again, such relatively low numbers helps.
The contact tracing very quickly identified that virtually every outbreak originated from a person entering Australia from overseas, there has been very little community transmission.
The Government introduced very strict weekly limits on people entering the country. I think it is currently 5000 per week and the vast majority of this number are returning Aussie citizens. Each has to isolate for two weeks (now at their own expense) in a designated quarantine hotel in the city of entry.
There has been issues with the management of this quarantine, most notably in Melbourne where the hotel security mixed with people in isolation and caused a relatively high increase in numbers through September. The Victorian government put much of Melbourne in to a strict lockdown.
The internal borders between states have been closed with the exception of essential workers for most of the year, but in the last couple of weeks the borders have been reopened and the Police manning those borders have returned to normal duties The recent outbreak in Sydney's northern beaches resulted in most states reinstating border controls for people in NSW or at least those living in the effected suburbs.
Mask wearing is or has been mandatory in some place's at times but not everywhere. Entry in to many shops, bars, restaurants and workplaces is via scanning a QR code or signing in on paper, but the same as anywhere else in the world many people choose to comply with all the requirements and advice, some choose not to and some fail to understand any of it.
As a result of the country's 'performance' most people's lives are pretty much back to normal, social team sports recommenced in June, we managed to complete a delayed 18 game Sunday League season (June to October) had our end of season do at the races, followed by a 8 game spring league, with the summer league (preseason tournament) planned as schedule to start mid Jan. We are at 50%(+) capacity at stadiums. We can mix in decent groups, go to the pub (sitting down indoors), have house parties, etc.
Absolutely, there has been some good governance throughout the year, but l believe luck and circumstance has played a huge part in Australia's Covid 'success' so far.