You need to work on creating a definite light source - although this is usually pretty hard with cartoon stocks/renders, which is why I tend to steer away from them, if it's for a SOTW, then I attempt to find a loophole using a photograph.
The Signature is a bit too long, and the main render of the Articuno is not very well placed - shorten the entire piece, and place the bird more in the center.
That's all for now

There's a fair bit more to work on, but we can focus on that another time.