Limbs Modelling - Joe the Echidnafox

Okay, now to begin a long multi-part tutorial on how to make custom Sonic style sprites. These tutorials will focus on modelling only, as we already have tutorials on how to shade.
Next, we'll continue with the limbs. The size of the limbs will depend on which style you intend your sprites to be in. The Genesis styles use bigger sprites than the GBA styles, so the Genesis heads will be bigger. This tutorial will use the size of Advance and Battle sprites. We'll be making arms and legs in this tutorial.

To start with, from the body shape, make a curved 3 pixel thick lineish shape from the upper edge of the body, and will extend the whole height of the body. Add another one on the other side(But make it less visible depending on the angle). Those will be arms.

Now, add 2 similar shapes that are a tiny bit more straight coming from the bottom of the body. Those will be the legs.

Now, I MUST note that the thickness and size of these limbs all depend on the character. Also, female character's limbs are more curved than the males, and the legs also are a tiny bit thicker around the top due to the hips.
Now, at this point, we'll start adding in designs or details. These all depend on the character. Sonic has skin colored arms, and blue legs. Also of note is that you don't need to add a design if you add clothes. Amy also has designs similar to Sonic.
Finally, clean up any uneeded pixels, fix minor things, and start shading, and you'll have your own limbs!