We have two different election processes.

The Lower House - House of Reps, we got a ballot paper for our local division which has about half a dozen candidates on average. You must number every square - if a candidate gets over 50% of the primary votes, he's it - if not the lowest candidate gets eliminated and their second preferences distributed, etc until someone remaining gets over 50%.

Now in the Senate - each state has several positions, and the system is much more fun. You can vote 'above the line' by placing a 1 in just one box, then your preferences are allocated according to the official party How to Vote cards - or you can vote 'under the line' where you must fill in all the boxes about 60 or so on average...

The following is a small contribution from someone who sent this to a list I run... :-)

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Strategic voting in the senate.

Do you know the strategic exhaustion trick? Preference the top candidates from parties you don't like last, then the next rank, then the next, meaning your preferences give least support to their first
(and most likely) candidate... Likewise, vote 1,2,3 across the ballot, giving the first candidate in each of your preferred parties a larger slice of your preferences pie.

As a simplified example for Queensland, not necessarily representing my actual voting intentions...

Group J             Group K               Group L
One Nation                               Family Farce

[49] HARRIS, Len   [50] HANSON, Pauline [47] LEWIS, John
[45] NELSON, Ian   [46] SMITH, Judy      [44]SKELLERN-SMITH, Tracy
[43] SAVAGE, James

As an example of the overall process I will use my intended voting pattern... As usual, I will be voting under the line. I usually give HEMP my first preferences, but this year it is so important that I will be voting HUTTON, Drew (GREENS) [1] and probably CHERRY, John Clifford (DEMOCRATS) [2] (despite my unease with the Dems and Family Farce getting along so well in the playground). Back to the "lesser" Greens and Dems for 3, 4 & 5...

This election is so important, in terms of avoiding another 3 years of smug misrule by the Johnny Howard and The New Right (Watch for their next album on Jackboot Records :-), that I will probably do something I almost never do, and give Labour my next 3 preferences and in "correct" rather than reverse order...

The nice people from the Socialist Alliance and HEMP will get preferences ahead of the Slowalition and their stooges. A straggle of loony fringe groups such as the Channel 7/"Oh, think of the children" nutter, Hetty Johnston (too easily exploited by the likes of Family Farce IMHO). Then down to Dear Pauline in the wooden-spoon position...

(BTW, which group are crazier, CEC or The Great Australians? So hard to tell without a few days of careful observation of their behaviour in the rubber room...)

Now, why not just vote HEMP and Socialist Alliance as per usual? The
reason is that preferences are not passed on as whole votes, but discounted (if a candidate gets up) and thus the higher the reference assigned, the larger the fractional vote that gets passed from hand to hand. Likewise the lower the preference, the small the fractional vote that gets passed on.