Here are a few tips that can make the prejudging easier :)
First, the judges doesn't always know who you are cosplaying (Shocking right). They might have gotten the reference photo like 5 minutes before they are to judge 20-30 contestants. It is fair to say that they don't really know much before they meet you.
Photo: Rune Olsen. Judges: Me, Martini's Workshop and JC from Fandomily cosplay. Cosplayer entering contest: Black Crane Creations.
That also means that sometimes they don't see if the fabric shade is a little too dark or if you a missing a rivet. So don't tell them ;) If you point out your flaws then the judges will definitely see them.
Of course if the judges asks you a direct question you have to answer honestly, but don't highlights mistakes if they don't ask.
My first question to contestants when they enter the prejudge room is "Hey, I want you to brag about your costume, tell me how amazing it is and what you are most proud of". Because cosplay is to have fun, even in competitions. And I know many contestants are very nervous.
Also most judges will ask questions to guide you, not to interrogate you ;) We don't know if you have hand sewn all the sequins of just bought a fabric with sequins on. Tell us all the little work you have put into you costume.
Once I was entering a competition and the judges only had two minutes to evaluate and for me to tell them about my costume. That is very short time to explain something I have spent four months building. Luckily I had made a list, with extra reference photos (that might not always be allowed, but best to be prepared). So I just started reading from that list and made sure I covered as much of my process as possible during my short time.
My Preparation notes for a competition with some wip photos to better explain. (Written in a mix of both english and norwegian)
Another time I didn't have a list I just started explaining from the top of my costume and working myself downward. Explain what I had done with wig, makeup etc ending up with leg bracers and shoes. That way I also got to talk about everything ;)
Photo by Joacim Schwartz
Wow, this is a wall of text, but it could help someone prepare ;) The play/stage part of the competition I will explain in another post.