Critique please!

So, I've just finished this and want to see if I can improve it?

Thanks

It's a nice start, but I suggest next time creating a new layer for the colour, instead of filling directly on the lineart layer. If you have the colour layer under the lineart, you avoid having all those white dots on the lines. I also suggest using a harder brush on this. The brush you used looks quite soft and feathery? I guess that's what you could call it. That's another thing making the lineart look like this.
Also, the credits on this image are not enough. DeviantArt is not a person, it's a website :P Next time, you need to link to the actual person ON DeviantArt in order for it to be proper crediting ^^

Looks great, Pegasus. In addition to the excellent points Siren made, I also find that when you use a straight white, it can later wash out the grayscale underneath that region when people recolor the character/design. To prevent this, people will often use a slight variation of the white color (maybe a bit of a gray-white, or a creamy-white). It still looks white, but colors better over many grayscales without losing the grayscale detail underneath the white :)
Hope that made sense. My thoughts feel scattered today.

Thanks for the feedback!