In my honest opinion, the best way for you to make your work stand out (apart from innate skill and a honed ability to write) is to write with passion, and to really care about what you're putting on paper.
Many people, myself included, go through VCE treating English as a chore - try to avoid this in the lead-up to your SACs and exam. I was lucky enough to find inspiration to write passionately (though it might have just been adrenaline, haha) when it mattered - but the best bet is to practice, practice and practice more until writing eloquently and fluidly is almost second nature.
By the time the exam comes around, you should be able to hit your paper running; but as always, the key is to care about what you're writing. Don't be mechanical and pump out a stock-standard response. Examiners aren't only looking for good pieces, they're looking for art.