Fans and light clothes, mostly.

A lot more people live out in cheaply built homes with small, barren yards and dark roofs that are literally designed for air conditioning. Older homes often have better airflow.

An example of a newer suburb in Sydney is Marsden Park: https://www.youtube.com/watch?v=WzV3H_K73To

I don't use/have aircon in my home in Brisbane and I get by fine :) Although it is nice to have aircon in the summer when I'm working on the computer and need to concentrate (my office at work is air conditioned, like most).