I would recommend building up on a few strong points. Most of the time, just having three armies at one place can at least keep opponents at bay, even though it's what everyone starts with.
And most of the time, you just have to pick the lesser of two evils, or the greater of two goods. Do you want to try and launch a mass attack from Australia after giving up the rest of your armies? Or would you rather stay solid all around, not letting others get your countries, but at the same time, spreading yourself out so that you're vulnerable as soon as anyone strong comes along.
The problem I find with spreading out territories, is that often, about halfway through the game, my territories are just way spread out all over the board. A few turns later, elimination. Staying strong at a few points is the way to ensure safety. Then again, they don't call it Risk for nothing.
