ANZAC’s role is very situational, and they must react to what the Japs are doing. For example, if the Japs are within 2 turns of reaching Sydney, and they have a respectable transport fleet plus air force, you HAVE to be honest and go on the defensive, being sure to maximize your builds (drop at least 3 units). I say 2 turns b/c if you wait until they are only one turn out, you will only be able to drop 3 units, which makes it easy for Japan to take.
Obviously you want to take Dutch NG for your bonus, as well as one of the 3 islands to boost in the south Pacific to boost income. A navy is a good strategy, especially if you are going for the KJF. One option is to move in sequence with the Americans, so if the the Japs attack they are attacking a larger force.
One thing I like to do; put an airbase in Western Australia and then build fighters, and funnel them to India. On the one hand this makes India much harder to take. Secondly, it frees up the UK fighters to be used elsewhere, especially the Middle East against the Italians.