I'll throw in my 2c here.
Generally, if you are doing a Point of View SAC, and you want to get good marks, you'll need to be highly convincing and present sound arguments. There are a variety of ways to achieve this. It's essentially all just using persuasive devices and sound reasoning in order to present a compelling argument.
First and foremost, I would decide upon the topic. You may want to discuss issues such as the treatment of Asylum Seekers here and abroad, Education Funding cuts and policies among the political parties of Australia (plenty of people on this board can help you with that), the importance of learning Languages in schools (for example, how many Australians can speak Chinese and how many Chinese can speak English, and how unjustified is this considering they're out biggest trading partner). You could present points of view on resource management, for example the Murray Darling Basin which provides a lot of our water.
Don't go writing a point of view on something trivial and seemingly insignificant, like the meat content of 4-n-20 meat pies, as some unfortunate chap in my year level did. Your issue needs to be sophisticated.
Once you've decided on the issue, it'll be a lot easier to figure out how to structure your piece. I wouldn't concretely decide from the beginning "I will write an introduction, three supporting paragraphs, one rebuttal paragraph, and a conclusion" if I don't even know what I'm going to be supporting or rebutting.
Let me give you just one example. Let's say I wanted to discuss the importance of learning Chinese in Australian schools.
I would give a brief intro discussing how China is Australia's biggest trading partner, how China is huge, how China is culturally diverse, how Australia and China share excellent diplomatic relations, how Australian foreign language education is underrepresented, and how beneficial it would be to have more Australians speaking Chinese.
I would then go onto a first main paragraph, probably to discuss trade. If there were more Australians speaking Chinese, bilateral trade would inevitably increase. This would lead to many flow on benefits for the Australian and Chinese populations. I would discuss these and see how it all falls out.
In the second paragraph, I would discuss the positive impact it would have on Australia as a largely multicultural nation. 25% of our current citizens were born overseas; that doesn't include the population of 1st, 2nd and 3rd generation Australian citizens.
In the third, I might discuss how China's rise as a superpower, despite slowing growth trends, will largely shape the future of Australia as a nation. I'd find relevant things to discuss.
And then, I wouldn't include a rebuttal. What the heck could I even rebutt? Something along the lines of "In the face of those who think that Australians should only learn English, they are wrong, and I am right". It sounds silly. There's no need for a rebuttal here.
What would work much more effectively would be perhaps your own manifesto or solution to the problems you have drawn attention to and raised. For example, you might suggest a policy, and implore the public (in your letter to the editor) to support it. For example, compulsory chinese education in school up until a certain point, or an appreciation of industry involving trade with China in school education, etc.
My end point is that you shouldn't plan a structure until you know what you are going to talk about. The structure should try to best suit your manifesto/aims in writing your point of view essay. Don't plan a structure until you have a point of view. When you've got a point of view, pick the best available structure.