I decided at the last minute not to apply. Why? because you've essentially got to be pretty extraordinary, community minded and be prepared to continue to give to Australia.
I know two students who progressed pretty far in the application process last year and still didn't get it and they're much more dedicated, academic and community minded than I am. It's not a scholarship where people can tell you what criteria you need to meet to reach stage 2 or 3 - you're either "worthy" of being a Tuckwell scholar or not. I decided there were much more deserving people out there than me.
Did you apply ? Did you discuss it with your school? They have to agree to support your application (and say they expect you to get at least an 95 (I think it was) ATAR). Maybe your school can provide you more information if you make it through to the other stages - good luck
PS none of the Tuckwell Scholars get under 98.5 (but it's not about academics)
Given that even if you're from a top school like Melbourne High, there's not going to be more than two students from your school in any given year. If you don't have the confidence to say that you are the most community-minded and talented individual from your school it's worth reconsidering.
But that having been said, it's always worth a try because never live a life with regrets (if you tried it, and you failed, that's fine! In my personal opinion, success in this application has to be built from a very young age, not something that you can just 'work hard' in the last 2-3 months or so and achieve it).
Personally I find it's a very rewarding experience, despite my low chance of succeeding, the potential future as an investment banker and having the chance to work with Graham Tuckwell is just too good an opportunity. Obviously the monetary incentives are great and all, but it's the opportunities provided in the experience that makes it most valuable from my standpoint.
Don't worry about the process in Stages 2/3 until you pass. It's incredibly tough (from what i've heard, leading in the high thousands figure in relation to applications and they only pick around 150-250 applications to advance).
Best of luck to you though, and others applying!