Fancy words?

I have the HSC as well and know how important it is to use language well, but the worst thing you can do is use "fancy" words wrongly or in an essay that doesn't suit it. It is best to use words that you know and use them well than to use a word simply because it is more extravagant. Examniners will know whether you're just putting words in or that you actually know how to use language well.