How I Studied for My Externals as the Dux of Brisbane Grammar School

David Sun accepting the Lilley Gold Medal for Dux of Grammar

Hi, I’m David Sun, the dux of Brisbane Grammar School. I achieved the top score in my cohort for four out of six subjects, and when I added up all my external marks, I finished with 222 out of a possible 225.

But here’s the surprising part: I never studied 6 hours a day — not even once. If you had sat next to me in the week before externals, you would’ve seen me spending most of my day chatting with friends, keeping calm, and making sure my headspace was right. So how did I still score so highly? Let me show you.

1. Consistency Beats Cramming

Most students think success comes from “beast mode” study sessions in the last week before exams. But that’s one of the biggest mistakes you can make.

I studied 1–2 hours a day, almost every day of Year 12. That may not sound like much, but here’s why it worked:

• I used active recall and spaced repetition (doing past questions, teaching concepts out loud, using flashcards) so my study time was high quality.

• I kept a loose schedule: maths practice every second day, science content review mixed with problem-solving, and weekly reflection on what I still didn’t understand.

• Over time, this daily habit stacked up to hundreds of hours of preparation — without ever burning out.

By the time mocks and externals came, I wasn’t “relearning” the syllabus; I was simply refreshing what I already knew. And because I had this consistency, I never had to sacrifice my health: I always slept before midnight, exercised, and kept myself mentally sharp.

2. Be a Little Obsessive

I’ll be honest: I can be a perfectionist. And in Year 12, that worked in my favour.

Whenever I didn’t know something, I couldn’t just ignore it. Even if it was the most niche dot point in the syllabus — or an obscure phrase on the marking guide — I needed to figure it out. This “obsession” turned into motivation. Every day, I asked myself: What tiny piece of the puzzle can I master today?

I kept track of my learning like a mental progress bar. Day by day, the bar inched closer to 100%. That habit pushed me to go beyond the average student’s comfort zone — where most people said, “this probably won’t be on the exam,” I thought, “what if it is?”

That’s how I became the first student to ever score 100/100 in QCAA Biology. Not because I was “naturally smarter,” but because I refused to let gaps stay gaps. My obsession made me complete.

3. Mindset Is Everything

Preparation isn’t just about the content — it’s about what’s going on in your head.

At the start of Year 12, I made a bold decision: I told myself that I would become dux, and I would aim for near-perfect externals. That mindset wasn’t arrogance. It was clarity. It gave me a reason to sit down every day for those 1–2 hours, even when I was tired or unmotivated.

When exam season arrived, this belief system became my anchor. I had already visualised myself succeeding. I knew that panicking would only waste energy, so when others were stressing, I stayed calm. My mantra was simple:

• I’ve done the work.

• I know the content.

• All I have to do now is trust myself and perform.

This mindset meant that even on tough papers, I never spiralled. I could take a breath, reset, and solve the problem in front of me. That calmness alone is worth as much as hours of extra study.

4. Learn With and From Others

Even though I was dux, I didn’t get there alone. Some of the most important lessons I learned in Year 12 came from my peers.

When I didn’t understand a tricky Specialist Maths proof or a chemistry mechanism, someone in my circle often did. By surrounding myself with hardworking, like-minded people, I constantly picked up new insights.

At the same time, I made it a priority to help others. I explained concepts to classmates whenever I could. Why? Because if you can teach someone else without confusing them, you’ve truly mastered the material. In fact, some of my biggest breakthroughs came when I was forced to break down complex ideas for others.

Community creates accountability, inspiration, and mastery. That’s why I never studied in isolation — and why I encourage every student to find peers who push them to level up.

Final Thoughts

I didn’t succeed because I studied more hours than everyone else. I succeeded because I studied consistently, chased complete mastery, kept a strong mindset, and leaned on a community of learners.

That’s the formula I used to go from being a regular student to dux of Brisbane Grammar School. And it’s a formula anyone can follow — including you.