Remove all furniture. Clean all dust and debris from your wood floor, using a 1 part vinegar and 10 parts water solution and a terrycloth mop. Let the floor dry.
Sand the floor. Go over the edges with 180-grit sandpaper and the middle with a buffer, which can be rented at a home-improvement store. Place a buffing pad on the bottom of the machine, and move it in a side-to-side motion. Vacuum the buffing pad every five minutes for best results.
Remove sanding dust, using a vacuum cleaner and microfiber cloth.
Apply a polyurethane finish. Use a paintbrush to apply the finish around the perimeter of the room first. Let this 3-inch strip around the room dry for 10 minutes. Then apply the finish to the middle of the floor with a long-handled paint roller with a 1/4-inch nap cover. Apply the first coat, wait 10 minutes, and then apply a second coat. The finish will be mostly dry in about three hours, but wait a week before you move the furniture back into the room.