1. Turn off the power to the circuit. This is the most important step, as it will help to prevent any accidents. To do this, flip the circuit breaker switch to the "Off" position.
2. Remove the cover plate from the breaker box. There are usually two or three screws that hold the cover plate in place. Use a screwdriver to remove the screws and then lift the cover plate off of the breaker box.
3. Measure the size of the breaker box. You will need to know the width, height, and depth of the breaker box in order to frame it in properly. Use a tape measure to take these measurements.
4. Cut the framing lumber. You will need four pieces of framing lumber that are the same length as the width of the breaker box. The height of the framing lumber should be at least 6 inches greater than the height of the breaker box. The depth of the framing lumber should be at least 2 inches greater than the depth of the breaker box.
5. Assemble the frame. Lay the four pieces of framing lumber on the ground in a square, with the ends of the lumber flush. Use a hammer to nail the pieces of lumber together.
6. Mark the location of the breaker box on the frame. Use a pencil or chalk to mark the location of the breaker box on the inside of the frame.
7. Cut the drywall. Use a utility knife to score the drywall around the perimeter of the breaker box opening. Then, use a drywall saw to cut the drywall out of the opening.
8. Install the frame. Place the frame around the breaker box opening and nail it to the studs. Make sure that the frame is level and square.
9. Install the drywall. Place a piece of drywall over the opening and nail it to the frame. Make sure that the drywall is flush with the surface of the wall.
10. Apply joint compound and paint. Use joint compound to fill in any gaps between the drywall and the frame. Let the joint compound dry completely and then sand it smooth. Paint the wall to match the rest of the room.