For me I like to keep a list of aircraft that I see come into YMML, so when I see one that is not on my list :D, and then I check the rego and see if its the next in line, like the Garuda that comes in daily, I've only been up to GPK for a awhile. or if its a different type of aircraft like the Malaysian Cargo, they have a couple of 747's that come in and they also use 747's from Southern Air, but a A330, hmmm, it was spotted in Perth awhile ago, so I've been waiting for it. And there's also the "Family" that make comments on the Thread here about new deliveries, so you no their about, and the threads by John and the Family in Perth are good to read and know whats about, it's good when you see them finally pay a visit to your space, mines YMML.
- Oh and the JQ A330 also was alphabetical - and it being very clean gave it away too.