Sonic Riders Style [UPDATE]

You seem to have studied official character models closely to get the proportions of not only the entire character but of minute details like her eyes and muzzle right, which is a definite plus and took me a long time to do right.

As for her design, the color scheme is pleasing and looks convincing for something out of alternate Sonic media, like the comics. I would suggest polarizing the two purples a little more, like making the one for her clothing a little bluer and the one for her hair a little redder, but you prioritize them well by clearly delineating one for hair and one for clothes. All in all she's definitely one of the better designed Sonic OCs I've seen.

Although you make generally good use of lineweights, some of your lines could be more even (such as on her hair and shoe) and I wouldn't really recommend a brush that's so grainy for the main outlines of a drawing like this; it just makes the result look sloppier. However, bonus points for incorporating the Riders cross-hatching effect in, which fits with her theme as a racer.

I'm docking a few points for vision and originality because cats (is that what she is?) and furry mammals in general are pretty generic as far as Sonic OCs go; I personally prefer ones of rarer species like reptiles, insects, and more obscure mammals like armadillos and elephants; characters like those immediately stick out to me. Don't be disheartened if you like her and use her in stuff, though; that's the most important. Also, I personally like to see backgrounds on even basic character shots - something simple and coherent with the overall color scheme like a light lilac background with basic shapes that relate to her design repeated like a wallpaper would help this picture out. All in all, though, decently designed character that could just use a little touching-up in the outlines.