Concepts

[Marth]

Any idea on how to shade the body? Because that's the only thing I dunno how to do.

[Black Sax]

Well, if you are going to shade it, do not shade it like you did. The head shading may be specific, but it looks very messy. When I shade my sprites, I usually do 4 shades for each color as long as it is used a lot. (The darkest being the outlining.) The origin of light should be the top, I think. I think that sprite would look good with no shading, maybe no outline, kind of giving it an arcade/ old school/ gameboy look.

[Omegakyogre]

Well, if you are going to shade it, do not shade it like you did. The head shading may be specific, but it looks very messy. When I shade my sprites, I usually do 4 shades for each color as long as it is used a lot. (The darkest being the outlining.) The origin of light should be the top, I think. I think that sprite would look good with no shading, maybe no outline, kind of giving it an arcade/ old school/ gameboy look.

Good god you're a one-trick pony. There's no rule that says he has to use 4 colors for shading, or shade a certain way, or use no outline, etc. etc. That's his decision. What matters here is simply how it looks, and if it looks good. Don't force him to change his style, rather: Suggest things to make the sprite stay in the same style and still look better.

I do think you (OP) should pick your light source and shade more directly from that light source, because it does look a bit messy right now. Personally, I'd through some anti-aliasing around the inside of that outline, it may make it look cleaner.
And, you should shade the body just like you shade anything else. Just don't get erratic. Start out with a single line that will define the edge of the shadow, and make it contour along with the curves of his body. Then make another one for his arm, since it juts out and will catch some light, and be sure to do that with anything that sticks out to where it will catch some amount of light.

[Gaia]

I suggest an independent lightsource for the body first. Then, follow the lightsource from the independent body towards the head and feet. Other than that, experiment until you get the best results.

Simple, yet effective. It's how most tileripped sprites are found within large enemies and certain characters that have more than twelve sets of frames (this case, the M&L games).