(I am a terrible criticizer so please don't kill me)
I love the eyes and expression on Mischief's face X3 The colors in the drawing compliment each other very well. I like the black top and bottom borders you've put on here. It gives the drawing a cool look. I like the way the hair and tail are shaped and all swishy. His ear are very nice too. ^^ The shading on Mischief looks very nice. I like the checker background (It looks so 3D!),
though the stains in the background draw your attention away from the main part of the picture. Mischief's arms and legs look very nice, but they're in the wrong position.
Overall, I really like the colors and shading and background and, in general, the picture itself! Good Job!
(i am so bad at critiques XD)