Start by pressing and squeezing the clay into a rough approximation of an elongated "teardrop" shape. Be sure to not make any air pockets in the clay. During firing the air inside these would expand, and "explode," ruining the mold.

Paddle the clay with the frosting knife (tool #4) to further refine the shape and to help flatten bumps on the the surface.

Use the fettling knife (tool #3) to scrape the surface smooth, and to fill in dents and hollows.

When the shape is to your liking, flatten one side by gently thumping it on the table. Leave the clay form out in the air for an hour or so to firm up.