Well, I do think you need to work on your backgrounds. Even is you don't like drawing them, its still good to practice.
Any way, let me put the goods and bads
The colors in this are very unique
The arms look great, You have improved, so do the paws
The way Wolfie's right paw steps forward like that looks good, also!
I understand that you have a cartoonish style, but Wolfie's back fur should be, shorter, smaller? The tufts of fur just look kind of odd.
The shading must be worked on to, although it is correct
The ears, they do not look like the right length, the right ear could be larger.
The curl... I'm not sure what kind of style you were going for but the curl should be skinnier at the end, unless thats just the style.
these are just my opinions on it XD I do think your art is good though, even though it may seem I don't like it ;v;
( Also, I'm sorry if the stars don't seem correct )
BEFORE I SAY A THANK YOU, ABOUT THJE CURL AND FUR ON THE BACK:
The fur on the back, it's a large mane. xD If it wasn't there, her back would be way smoother and more.. Well, less fluffy.
And the curl, I draw it in two styles: One, hetalia style: At the end it get's fatter and two: Like you said, it's just skinny all around.
I actually aimed for not making the ears the same length, I normally do. xD It's just prospective, which isn't the best in this drawing.
And yes, shading and background. The reason why I don't do backgrounds is 'cause I never know what to make them like, so I quickly made this one for the drawing, not spending much time on it.
Shadiiinggg, I tried to shade as well as I could, started out well but I kinda gave up and got lazy near the end. Plus; I noticed that the light source is beating on the shaded part, which is not correct.
All together, I kinda winged it. c:
Thanks for the critique, though!