I have made antiqued clay ornaments in the past, and since it's such a fun and easy project, I thought I'd share pictures of my creative process with you. If you have questions, please feel free to ask!
I was happy to finally find air-dry clay locally - I'm sure other kinds of clay would work, but I've heard that a slower drying time keeps the clay from warping. Oops...I dried mine outside in the tropical sunshine...so mine did warp a little. Not sure what brands would be available where you are...the brand of clay I used is DAS. I rolled the clay out to 1/4" thickness (note: use a craft-dedicated roller for this!). To ensure an even thickness, I put the clay between 2 rolls of 1/4" wide tape as a guide for my rolling pin.
After trimming, poke a small hole using a stylus. Be sure to poke through from both sides so the hole is even all the way through. Allow time for your ornaments to dry thoroughly on a flat surface. You can turn them occasionally so they dry from both sides.
When the ornaments are dry, color in the raised areas with alcohol markers (any other non-waterbased medium should work). I used Neopiko markers on mine. No need to do any shading - keep it simple.