Just to let you know, I'm also a cosplayer and like you, I make my own costumes and props. But you're WAY much better than me. I'm not that good and. I'm not an expert in cosplaying but well, I'll try to give a good critique.
To start it off, It was really eye-catching. I don't usually look at my deviantwatch messages but this one caught my attention. That's one point.
For the costume, The costume looks good. Great actually. You could see all the parts of the costume in the picture. Although I would've liked it better if you raised your leg on the right side a little so that the shoes would be seen clearly. The costume's not exactly like the character's, which is Ciel Phantomhive. But it's close and the concept is nearly the same. I know most make some changes in cosplaying, making it look much better but sometimes, it changes a little bit too much that you wouldn't know it's that particular character. But for the costume itself, it looks great and so elegant. There are some accessories that are a little bit too much but if you look at it over all, it's just about fine. That's the second point.
My third point is on the photography. I'm not a photographer and nor I am good at it. But as a viewer's opinion, it's really clear. The back ground is very relaxing and calm, not overpowering the main focus of the photo. The background's color is actually giving you, the cosplayer more impact in a way and the oufit's concept and the background fits perfectly together and gives you a nice glow and light.
Overall, this cosplay is great and the photography side is good as well. To you, as the model and cosplayer, is gorgeous and have good skills!
I think you have done a brilliant job with costuming and make-up, its pretty flawless, although the costume might be a tad much. That being said, it is Victorian-esque, and they were all the more the merrier in the noble class, so maybe I am being a bit too minimalistic on that. The lighting confuses me a little, I see the effect that is being attempted, but its not quite there. I think its missing a more directionalized/dramatic view, or perhaps its the filter that isn't doing it for me (but that's more of a personal preference, so you can disregard my view on filters). I like the venue too, it works well. What exactly are you trying to get across with the pose? Its ok, but lacking intensity. I do like it though, it caught my attention which s always good. Good luck on future endeavors and keep it up ^_^
Yes, is the demon version, well not... is the cover magazine, a Yana Toboso design of Halloween Costumes, but... I think this design is a spoiler of the future of Ciel!! or not? xD haha Thanks The datails and the tail, is my idea )!