Create a round ball from the clay. If making the planet Venus to scale, it should be slightly smaller than Earth. Consider writing the name with a toothpick on the surface to help with identification if making multiple planets. If you plan to hang it from the ceiling or a mobile, run a string through the planet when forming the initial clay ball or secure a paper clip into the top so a string can be threaded through it later.
Dry the clay following the directions on the packaging. Some clay can be baked in the oven to quickly harden it.
Paint the clay planet using yellow and brown paint to match its hot ember color. Provide pictures or models as guides to the details.
Allow the paint to dry. Consider hanging the single planet or creating a planetary solar system.