Just fiddling about in MS Paint and I figured I'd whip up something quick and pixely. It's incomplete and I forgot to save all stages (sorry, no pictures of creating the lineart) but it shows one way I colour in MS Paint.
As you can see, once I settle on the lineart I then plan the lighting. I figured a purplish light coming from beneath and to the left would be nice. I then placed the markings and shaded, adding a yellowish light above and to the right to balance the purple. Purple and yellow are complimentary colours, so they balance nicely. You can see I tweaked the purples quite a bit trying to find something that felt right.
It's not really a tutorial... I don't know, just thought it might be something interesting to upload as I've not done pixel art in a while.
About forty-five minutes with a touchpad in MS Paint. The larger Muchi was resized using XnView.

I will probably finish this and make an avatar/icon of it.