Australia is as wide as Europe, so the art of a good trip is choosing well and flying between regions rather than driving them. A classic first visit combines Sydney, the outback at Uluru, the Great Barrier Reef with the Daintree rainforest, and a wildlife island in the south.
The seasons shape everything. The tropical north has a wet season from November to April and a dry season from May to October, while the south is better in the warmer months. We sequence the route so each region is visited at a good time of year.
The honest caveat is distance. You need at least two weeks, ideally three, and there are no shortcuts on the flight from London. A stopover in Singapore or Perth on the way out makes the arrival far kinder.