Use a circular saw to cut framework for a concrete pour. Build the patio base 8 inches deep. Use 2-by-8-inch boards to construct the box to hold the concrete. Be sure to add metal gridwork to the framing before calling the concrete delivery truck. Construct the slab to support the weight of the shed so the building will stay in place over many years. Never build a shed directly on the ground.
Use 2-by-4-inch boards to build the shed's basic framework. Construct the wood skeleton of the building by installing wall studs and ceiling rafters on 16-inch centers. Secure all framing with stainless steel screws installed with an electric screwdriver. Build one wall section at a time, and check all work with a carpenter's leveliing tool. Leave openings on each wall for a window.
Finish the roof area. Nail 1/2-inch plywood to the roof of the shed to cover the rafters. Install tar paper and asphalt shingles. Cover exposed rafters by nailing on fascia boards. Enclose the bottom of the exposed rafters with plywood. Add guttering to the perimeter of the building, if desired. Caulk all appropriate gaps.
Install aluminum-framed sliding windows in spaces left for windows. Secure the framework of the windows to the wood framing using stainless-steel screws. Add exterior-grade siding on the outside of the shed, caulk and prepare to paint exposed wood. Use two or three coats of semi-gloss paint.
Use heavy-duty hinges to hang doors for the entrance. Finish up the entrance with a concrete ramp for a riding lawn mower or other equipment to be rolled into the shed. Construct the ramp with plywood pieces left over from the roof construction. Mix bags of concrete to pour into the framing. Finish to a rough texture with a concrete trowel.