100 Days of Vector Art
I undertook a 100 day challenge where every day I would create a small vector art. I spent the first 25 days doing generic character designs mostly to familiarize myself with Adobe Illustrator.
The last 75 days were spent doing more familiar characters. This put me in a position where I could start pushing and pulling key features to see how much I could leave out while still keeping the character recognizable.
At day 50, I started adding textures and gradients to give each character more depth.