The VG Resource

Yoshi in the Modern Genesis style

C+C plz
(Oh and I didn't make ther mario, he is just a size ref)

Avoid using four shades for any colour that's not in the white to black pallete line- so on the green, I suggest removing the lightest shade (the highlight shade). Instead try maybe the lightest brown (... it may work), or a grey.

I'd also move the highlight on the nose more to the left and increase it in size slightly. Shade the underside of the nose more heavily, accenting the rounder shape more.

Other than that, I think the head is too big, but I'm not really an expert on Mario, but that's just what I think I'm seeing here.

EDIT: Tail looks a wee bit nubby too.
EDITx2:

To show you what I meant- the style is very shading heavy with outlines mostly avoided. The brown didn't work as a good highlight colour on the green, so I went with the grey/white. Also shaded the eyes more. Hopefully this'll help you get an idea of how this style is done. Really thinking the head needs to be downsized, though.

the arms are just a little too thing and small and add a tad more of darker green shade. I'm loving the mario.