Practice cutting into the cardboard with different tools. Score one side of a piece of cardboard with a utility knife cutting into its exterior layer. Cardboard usually has three layers. Two are exterior flat layers and it has an inner corrugated layer for added strength.
Bend the part you scored, which should cause the cardboard to stand up. Cut through the cardboard by cutting into the opposite side you cut into first. Test your scissors by cutting into the cardboard.
Pull up an edge of the cardboard with your fingers to remove the outside layer. Observe its weight and compare its characteristics with the complete cardboard.
Join two pieces of cardboard using duct tape. Tape another two sections with clear tape. Test which is stronger and which is aesthetically more pleasing. Glue two pieces of cardboard together. Wait until it dries and test its strength.
Paint the cardboard with various types of paint, such as watercolor, acrylic and tempura. Experiment with applying the paint with paintbrushes. Allow it to dry to observe the results. Consider using spray paint or different application tools, such as sponges and stamps.
Research other artists who have used cardboard as a medium, such as Chris Gilmour and Mark Langan. Observe how they use the material to accomplish their sculptures. Consider incorporating some of their ideas into your sculpture.
Draw a preliminary sketch for a cardboard sculpture on your sketchpad with a pencil. Consider the size, the final colors and views from all sides. Use your new knowledge of cardboard and how it cuts and how you can connect pieces to help you form ideas for a sculpture.