We're going to adapt our mascot for this exercise, but you can start from scratch if you'd like. Depending on how your work is, it may be easier to have a blank canvas. Regardless, these steps will apply
Rough Sketch
This will build the foundation of your final artwork, and because expression and exaggerated poses are so important, you'll want to make sure you're solid here. Keep your forms round and bouncy. We built on sweeping, curving lines to form a skeleton.
Refined Sketch
Once you have your pose and rough shape blocked out, refine your sketch with more details and those elements to enhance the design. These clothes, accessories, and other components will make it into the final illustration.
Inking
Animation relies on consistency because the artists must redraw thousands of times. Variation in line weight makes the characters wiggle, which is often ugly and distracting. When inking your own work, stick with a pen that has a consistent line weight, such as a monoline brush.
Color and Detail
Early animation used flat blocks of color painted on cellophane or plastic "cells" with shading and detail reserved for the static backgrounds. Color your character in flat greyscale.
You'll notice that our illustration incorporated halftones to align with our original mascot design. This is not historically accurate. However, as we mentioned before, style comes down to your choices. You can move away from the design standards of your reference so long as it is done thoughtfully and intentionally.