I think the main problem is the fire is drawn looks far too structured and static. More realistically, fire is flowing, refer to your own signature and observe how the fire is constructed on Infernapes head. The fire is based on a red 'streamer' with red flicks inside it. More notably, it also is supported by the yellow layer, which does not reside typically in the center. I had a quick go at drawing the fire I mean, and I used your snake as an example albeit less 'sugimori' like in it's structure but take what you will.
I don't think I spent any longer than about 5 minutes on this example, but it sums up the point I want to make about the fire works. Perhaps I could have spent a bit more time making it look like it was flowing with wind, but it demonstrates the effect I'm talking about well enough.
If you're going for sugimori style stay strict to his palette usage and make sure your lines look much thinner and cleaner than they are. Also, watch the lightsourcing. His face suggests his fire is in front of him when it is behind him. Other than that, I think the concept itself is pretty faithful. Keep up the good work.
Yeah that makes a lot of sense, I see what you mean, that fire looks a lot more natural. Thanks! ^_^
Unfortunately as I don't have a PC just an ipad the bamboo app I'm using isn't the best for thin lines but I get what you mean about the palette (something about the colour never looked quite right to me) and the shading (my first attempt at it, took my forever to work out how to do it >_<)