After getting the Light Shoes (and Crystal Ring to speed up the
process), go to the Casino area, and step on the button to make the
rings appear. You can do this repeatedly for more starting rings.
Note: The ring limit can exceed 999, but you cannot tell exactly how
many you have. Listen for the extra life sound to keep track of them.
When you getting as many as desired, go to Emerald Coast, and complete
the level without getting hit to be awarded with however many rings you
have collected. Go to Chao Garden, then the Black Market, and use the
rings there.