I'm doing an animated frog for Bennu, so I started by doing the frog sprite first.
Below are the steps the sprite went through in its creation.

1. I searched the net for reference pictures and drawings.


2. Paths were used to create the main shapes of the frog...


3. ...and the animated parts were left on separate layers so they can be used as separate images.


(These separate images will be rotated and translated to animate the frog)


4. Shadows and highlights were used to make the frog more 3-D (the amulet on the top-right of the reference images was the main source for this)


And it's (mostly) done. :)