Cool, I am glad you like it
I will improve your princess also, just by changing some colors and minor improvements. I did it on my lunch time ^^
Another advice I could give, is that too much black lines (black pixels) is not good. For example, the hair, if it is blond or brown, can be draw with a line a bit darker around, but not black, to "lighten" the drawing visually.
Anyway, I am not very good at pixel art, but some rules that apply to drawing are the same