I first heard about the UKChO shortly after I moved to the UK. One day, I happened to come across someone talking about it on Facebook, and that was the first time I realised there was a chemistry competition like this in the UK. It looked quite interesting, and since there honestly wasn't that much to do at the time and I had plenty of free time, I thought I might as well give it a try.
So the first thing I did was open a past paper and attempt it. By the time I finished, I was completely overwhelmed. I couldn't even do the basic calculation in Question 1, and I struggled to understand a lot of the chemical terms in the paper. So I did something that seems quite funny looking back: I went straight onto 'Taobao' and searched for a "UKChO course". I actually found one, although it was a recorded course from the previous year's preparation programme, and it still cost me more than 100 GBP. Since I had already spent the money, I simply followed the course lesson by lesson and worked through it properly.
Looking back now, there wasn't really any magical "competition technique" in the first part of the course. Most of it was simply helping me build up my chemistry foundation in advance. To be fair, the main UKChO content beyond the standard school syllabus was things like electrochemical cells, crystal structures, NMR, and some additional organic chemistry. At that point, I hadn't even formally learnt much of the AS content, let alone A2 Chemistry. So while keeping up with my normal chemistry lessons at school, I was also using the recorded course to learn AS and A2 topics ahead of time.
After finishing the entire 30–40 hours of recorded lessons, I foud out myself had a much clearer overall picture of the chemistry and the topics that could appear, but when it came to actually solving UKChO questions, I was still struggling. By then, it was already January, with only about three weeks left before the ukcho. So I decided to go through the entire course again from the beginning. It was only on the second watch that I realised how many details I had missed the first time, and how many things I thought I understood but actually didn't. So I worked through the videos again while gradually filling in those gaps.