The demands of arrival in Sydney may prove almost too hard to bear after your long flight. The airport is just as overcrowded and under-efficient as those in the States. If you've scheduled an immediate domestic flight to another city, you probably can't make it. But the airport's porters can help greatly—for a few American bills. Aussies avoid tipping unless for extra service. Help at the airport often qualifies.
Generally, if you plan to go anywhere else in this enormous country, you should stop over in Sydney for a night or two after your arrival. You need the rest, and this is a glorious place to get it. Many of the big hotels are outrageously expensive, but others, more reasonable, can be found. And at the time of writing, at least, the exchange rate is highly favorable to us Yanks.
Australian money is simple, attractive and easy to learn—coins for one and two dollars, bills for five, ten, twenty, fifty and a hundred dollars, growing in size as their value goes up—a convenience when paying for a taxi at night.
As the regretful time to leave Oz approaches, check to see if you'll need a departure fee and keep it handy. And have a good look at your last Australian sunset. The whole trip's worth it.