If Crocodile Dundee is your idea of an Aussie style icon, think again: Melburnians and Sydneysiders are as fashion-conscious as New Yorkers. In the big cities, slop around in shorts and you might as well wear an "I'm a tourist" badge. Instead, pack nicer jeans, Capri pants, skirts, or dress shorts for urban sightseeing. A jacket and tie or posh dress are only necessary if you plan on some seriously fine dining.
Things are a bit different out of town. No Aussie would be seen dead on the beach without their "thongs," as flip-flops are confusingly called here. Wherever you are, your accessories of choice are high-quality sunglasses and a hat with a brim—the sun is strong and dangerous. Carry insect repellent and avoid lotions or perfume in the tropics, as they attract mosquitoes and other insects.
A light sweater or jacket will keep you comfy in autumn, but winter in the southern states demands a heavier coat—ideally a raincoat with a zip-out wool lining. You should pack sturdy walking boots if you're planning any bushwalking, otherwise sneakers or flats are fine.
Australian pharmacies stock all the usual hygiene products (including tampons and condoms) and toiletries, plus a whole lot of fabulous local brands often not available overseas. There's also a mind-boggling range of sunscreens and insect repellents, so have no qualms about bringing everything in travel-size bottles and stocking up when you arrive. Oral contraceptive pills are usually prescription-only, though emergency contraceptive pills are available over the counter. Grocery stores and supermarkets frown on your using too many plastic bags—carry a foldable canvas tote or reusable shopping bag, and you'll blend in perfectly.