1. In a well-ventilated work area, place newspapers over work surface.
2. Pour quick-drying concrete into a plastic container. For each tin, you'll need about 8 cups of dry concrete mix. Mix it with water according to the directions. To slow the drying time, add another cup of water to the mixture. Just before you pour, spray the form with nonstick cooking spray. When the mixture is the consistency of cake batter, pour it carefully into the form.
3. Smooth out the concrete and add embellishments, such as rocks, marbles, or small toys. Write your name with a small stick and make a handprint or footprint if desired. Work quickly. Wash hand or feet when done. Let the plaque dry.
4. Remove the plaque from the form. Paint it as desired. Let the paint dry.