Measure the desired width, depth and height of the cabinet you are building. Write down the measurements. Lay down two 4-by-8-inch plywood sheets and draw the two side panels for the cabinet, using the height and depth measurements.
Lay down two additional sheets and draw the back and door panels measuring the height and width, minus the thickness of the wood on the width measurement. During construction, these panels will go between the side panels. Take the two final sheets and draw two rectangles measuring the width and depth for the top and bottom cabinet panels.
Place the square ruler on each of the corners of the six drawn rectangles to ensure they are even and straight. They must all have 90 degree corners.
Cut the cabinet panels using a table saw. Avoid saws that produce slower cuts, such as a handheld saw. Instead, use an electric saw to cut so the plywood does not crack during cutting. Wear safety goggles at all times while cutting each of the cabinet panels.
Sand the sides and edges of all panels cut for the cabinet using medium-grit sandpaper. Because plywood consists of thin layers of wood, it tends to create small cracks and splinters during cutting.