Construct a blade. It should be made of a lightweight yet strong material, like aluminum, heavy-duty plastic or thin plywood. An old snow shovel blade will work perfectly, or cut a rectangle of plywood or heavy plastic about 1 foot wide, and 12 to 24 inches long.
Choose a pole. The pole can be as short as 6 feet, but a length up to 16 feet will enable you to rake snow from the roof without standing on the roof or using ladders. Most large hardware stores sell aluminum and or fiberglass telescopic poles in various lengths, including telescoping poles that are easy to store.
Attach the pole to the blade in the blade’s center by screwing a small block of wood to the center of the blade, then attaching the pole to a hole drilled in the wood. Your snow rake will roughly resemble a men's razor.
Attach two triangular supports made of 1/2-inch wooden dowels. This will reinforce the blade. Screw one end of the dowels to the side of the blade and connect the other end to the pole, forming triangular braces.