Wow that's a goldmine of information! Thank you for sharing.

Banding is explained in this amazing series of posts by cure

Thank you very much! I can tell the bottom of the buggie doesn't look right but am unsure how to fix it. By banding do you mean too many colors? I think I might make the outline on the bottom of the wheels all black. when I put the sprite on a dark background the bottom of the wheels look textured. I'll play with the contrast on the wheel colors. Thanks so much for the advice! Trying to make it look the best I can.

That's a big improvement! The only advice I can think of is that maybe the banding under the hinge and on the sides of the baby car could be cleaned up, and maybe the purple AA is overdone on the wheels. Maybe more contrast in the different shades of grey on the wheels, too?

Looks great, though!