I think the characters from Madoka Magica are still rather popular, so that could be an idea.
Kuroko no Basket is pretty popular now too from what I can tell, so Riko or Momoi might be well received.
The anime [K] is still new and also popular from what I can tell, and Neko, Anna Kushina and Seri Awashima are the most notable females in that.^^
Otherwise your guidelines are really vague. Do you care if you match the character appearance wise? Does the outfit have to be simple or cover you up a lot or something? Any genres you like etc?
| gamescom | Connichi | Frankfurt Book Fair |
~ ♥ ~
| teenage!Uta (Tokyo Ghoul) - 70%|
| Firecracker Jinx (LoL) - 20%|
~ ♥ ~
| Facebook | Tumblr | WorldCosplay |