Hmm, this may not be received too happily, but I'd say the looks of the cosplayer: how similar their appearance to the character (facial structure, height, figure) is/how attactive people perceive them to be etc.
That doesn't mean that I think something like that should be a requirement at all, though.
And of course also a certain devotion to the costume, details, posing, props and make up.
| Connichi | Frankfurt Book Fair | AniMaCo |
~ ♥ ~
| Homura Akemi - 80%| Rin Matsuoka - 75%|
| Yuu Kashima - 70%| Nagito Komaeda - 55%|
| Seishuu Handa - 50%| Uta - 40%|
~ ♥ ~
| Tumblr | deviantART | Cosplay plans | WorldCosplay | Cure |