Unzip a luggage cube. Often the cubes have mesh tops to allow for airflow. This is especially helpful for dirty clothes you must pack on a return trip.
Fold each piece of clothing as neatly and tightly as you can. You might want to try rolling your clothing or socks.
Place one piece of clothing at time in the base of the luggage cube. Continue stacking until the folded clothing is just above the wall of the cube.
Pull the top of the cube over the clothing and press down.
Zip the sides of the cube.
Place the cube in your suitcase.