You can try trace items on the USPS website - usps.com
Sometimes the Global Priority packages are logged onto the USPS online tracking, but only on submission of the item. It is not logged on receipt or intransit. But this is not the norm for Global Priority. It is not supposed to be tracked.
Global priority should take only about 1 week to arrive, but the thing is, it is NOT Guaranteed, and it is only guaranteed to begin its trip that night out of US. It can still be delayed in customs (and it will depend on the amount of mail Customs has that it may slow it down). Then it is not Guaranteed to be shipped in an Express manner once it arrives in Australia, so within Australia, it can go along with standard mail so can take it own time.
Next step up is Global Express Mail. This is USPS's Express mail, and this is tracked online and should only take a few days to get here (barring Custom's delay).
Then the premium is Global Express Guaranteed or GXG (Guaranteed Delivery by a certain date). This usually arrives within 3 days. It can be tracked online. It is usually sent by FedEx and so you will get a drop off by FedEx not by Australia Post.
Then there is Registered mail, which will give you online tracking, but is slow to arrive. Gets sent with standard mail.
So if you want something fast and with tracking, get it sent Global Express Mail. This usually costs about $20 for a few cards (depends on how it is packaged). For high end stuff I would recommend GXG.
For most of my stuff, I request Global Express Mail.
Though, I did have one item sent by Global Express Mail that did arrive, but they did not log the Tracking number, so it did not end up being traced on its trip to me.
Ersk