Research goddess figurines to generate ideas and determine the particular meaning you want your goddess to convey. For example, goddesses with wide hips are often considered fertility figures, Minoan goddesses often held snakes in their hands and several religions depict warrior goddesses with varying attributes that symbolize the goddess' powers.
Sketch out your goddess with paper and pencil. Draw a couple of practice sketches as you work out the proportions of the goddess' figure, the posture you want her to hold and what details, if any, you wish to have. Once you've settled on a particular goddess form, note the areas where the sculpture might be weak, for example, the places where the limbs extend. You'll want to pay particular attention to these while building the sculpture's armature.
Make a finished sketch in the size that you want your goddess sculpture to be. Most are around 12 to 18 inches.
Crush aluminum foil into a head-shaped figure and cover it with a thick layer of clay. Start modeling the goddess' head. This may take a couple of tries to get right. Remember that eyes appear halfway down the head, not close to the top (hair makes people's faces appear otherwise). Press small indentations for the eye sockets, add a little clay to create the nose and the apples of the cheeks, and a small line will suffice for the mouth. You can keep the details relatively rough, since you'll be painting in the facial features later.
Use aluminum wire to craft an armature for the body. Clay is fragile, after all, so use the armature to support weak areas or areas where there will be a lot of clay.
Start with the torso, using your final sketch as a guide. Fasten arms and legs by crimping lengths of aluminum wire to the torso. You may want to use two lengths of aluminum wire in order to create a stronger armature.
Pack clay onto the armature so that it is completely covered. Begin modeling the features of the body. Use clay shaping tools to cut off excess clay as well as carve in the detailed areas.
Fire the clay. Depending on the type of clay you bought, firing times can vary, so read the instructions on the clay package carefully.
After the the clay of your sculpture has hardened and cooled down, draw in the details you want to paint with a pencil. Use acrylic paints to add color, facial features and other details to your goddess sculpture.