What you need:
Clay charm painting kit (purchase here)
You may use cookie cutters or toys for stamping patterns on the clay.
Knead the clay and flatten the clay as per desire thickness.
Shape the clay freehand, or use a cookie cutter to cut the desire shape. Stamp patterns using materials around you.
Use a hollow rod to punch a hole for the charm string. Air dry it for a day or two.
When the clay is completely dry, paint it or decorate it using your own creativity.
Leave it to completely dry. Paint with a layer of varnish for glossy look.
All done, a homemade gift from kids!