Okay...well, I suppose I'm not exactly the most qualified to give advice... I've only done a couple so far, myself, but I'll try...
The fur is very well done! I like the eyes, although there is some brown from the fur poking through. To make it easier, you may want to use layers... which I'm still attempting to understand for myself. However, that way you can keep your lineart and colouring separate, and erase each individually.
For the white stripe down the face, maybe use a the airbrush thing (a larger size?) to make it more even. And for the tongue, colour it in a bit more, so the lines and the faint colouring don't look so separate. As well, you could also just go over things with a slightly darker shade in airbrush (more smooth) or watercolour (more defined) for shading
Hopefully that helps?
