Make a scan of your passport, drivers license and medical insurance details and store it in the cloud ‘just in case’. Let at least one trusted loved one have access to that information in case of emergencies.
When you are on the plane, they will ask you to put down the Aussie address that you’re going too. For ease, even if you’re going somewhere first (a la Susan and Karla) just use 2 Duke Street, West Launceston, Tasmania 7250 (my parents address). Lets make customs think mum and dad are having a massive, summer-long party! FYI my cell is +61.417.380.675 as the contact number.
Take a surge-protected power board so you only need one US-to-Aussie power adaptor so you can plug all your devices into one outlet. Be aware Aussie outlets are higher voltage than US (by more than double I think) so protecting your electronics is important.
Hot tip: when you plug something in to a wall socket, you need to actually turn the power point / outlet on with the switch. This sounds like silly advice, but after living in the US I’m out of the habit now, and often catch myself plugging something in to charge then coming back to find I never turned it on which is annoying to say the least, and painful if it’s something you really need like a GPS unit or camera battery!
take a refillable water bottle. Aussie water is really good quality (Tassie’s is, of course, the very best) so you can fill that up on the long haul flight to avoid buzzing for the attendants and save a tonne of money buying bottled water during the trip. Hot tip: make sure you haven’t filled it right up before going through security as you’ll have to gulp it down quickly!
make sure your carry-on contains at least your basic toiletries, a change of clothes and all essentials like laptop and camera to avoid the “I don’t have my suitcase for five days so am wearing the same clothes in every photo” experience I just had in England, ha ha!
this link here covers a bunch of other stuff like how to get a tourist refund on tax you paid on products (especially wine and spirits); details on our currency, climate, where US embassies are located, what happens if you fall in love with someone while visiting and want to get married (it has happened!); maps, apps and general touristy info.
and here is another link to even more helpful tips – made me feel happy to see some of mine in here, there are loads of other good ones too!