With this quick mod, you can make your favorite heels a bit more stable in 10 minutes using only some scrap fabric and spray adhesive. So quit worrying and start walking tall.
Step 1: Measure and make initial cuts
This yellow fabric I found was about the thickness of tee-shirt cotton, but with a bit more texture.
Using some chalk, a pencil, or a pen (if you don't care about the marks), roughly trace the outline of your foot. Cut out.