Presentation must always be at it's peak
So, I've went to a ton of Olympiads, science fairs, congresses, fests etc etc and I mainly work with Robotics which means, no matter how hard I work for it, there is always a chance for last minute betrayals. But interestingly a lot of my winning projects fall into that category. Almost all of them actually. So, I sat down and noticed a pattern, whenever my project worked it's best, I presented it with an average speech, taking about a minute or so explaining each feature. However whenever a part of my robot wasn't working, I took out some extra time to explain exactly what and how the feature was supposed to run which made the feature sound even more impressive then it was since building a robot isn't as easy as it sounds and it really brings out what went behind that. Another thing is I always tried to make up for a faulty project with a positive presentation, whatever happened, I'd keep smiling and explain the solution, there could be a murder going on behind me but I'd still present with my peak presentation voice and not just for judges, anyone and everyone that saw my project, even outside the event, I will present it to them in the same manner. And that kind of perfected the speeches without even trying or memorising and since I had already faced all sorts of possible reactions, it's basically like reciting a story when the real judges come.