First, plan the path for the new wiring and remove the baseboards where necessary. Use a sharp drywall knife to cut the caulk and paint sealing the top of the baseboard to the wall.
Run the new cable from the source electrical box, through the notches and into the new outlet box. Pull an extra 8-10 inches of cable into each outlet box to allow for stripping and connecting the wires.
After choosing the electrical source, decide where to cut the walls and ceilings to run the new cable. For example, to run from an existing wall receptacle up to a new ceiling light fixture, a small hole should be cut in the corner where the wall and ceiling meet. The top plate is then notched to pass the cable and afterwards a metal plate is attached over the notch to protect the wires.
Mark a straight line along the wall a few inches from the floor just below the top of the baseboard. Cut the wallboard along this line using a drywall saw for the hollow parts between the studs and a drywall knife to cut over the studs.