It depends on what you're cosplaying, for me.
Like for Homestuck, since a lot of the costumes are very simple, adding the extra details, or just up-ing the design is really great, like the Fancy Dreamers, or the Fancy Tiers!
But for anime, it's different. The more accurate you are with the costume, the better. The right shoes, the perfect wig, the contacts, the make up, they all make an anime cosplay eye catching.
Next Convention: Anime Detour
Peko Pekoyama- Super Dangan Ronpa 2(95%)
Kiryuin Satsuki- Kill La Kill(95%)
Tycho Science- Diebuster