Loudmouth it's very simple- you list every candidate, and rate them from best to worst (the most effective way to control the preferencing arrangement yourself)- or you can vote 1 on the only remaining party you might actually like after doing some research (but leaving the rest means that you entrust this party with your preference), or you could just leave it blank, its up to you.

For me;

1- Greens
2- Any independents that match my important viewpoints (on say, democracy, privatization and such).
3- Single-issue parties relevant to me
4- One Nation (plenty I agree with that would make politicians take note, but plenty I dont so not too high a place)
5- Family First (same as above, though the added implication that I would support the 'stronger family/more religion' movement forces me to put them lower than ON)
THEN there are the parties I absolutely have no support for
6- Gray-voters, Fishers and Shooters (just unimportant lobbies to me to put the really bad ones lower down)
7- Communist parties
8- Libertarian Parties, other christian parties, miscellaneous Small L liberal parties
9- Democrats
10- Nationals
11- Liberals
12- Labor

You can arrange it however you want- just remember, that by voting with all numbers, every vote for a useless party HIGHER than a party you earnestly despise REDUCES the vote the second party gets, so every vote counts!