Clean the floor with warm water. Use a sponge mop to do this, as a sponge mop is less likely to damage the marble floor that a cotton mop.
Remove stains from the floor. You can use a mixture of ½ cup hydrogen peroxide in six cups of water to do this. Dip a sponge in the mixture and gently rub the stain.
Hone the floor. To do this, use a 600 grit sandpaper to wet-sand the floor. This means that you must keep the floor and sandpaper wet at all times. This is done to simply remove surface imperfections. If the floor is heavily used, this may be the only way you can fully restore the floor.
Buff the floor using a buffing pad on a floor buffer. This will smooth the surface of the marble and begin to create a shiny finish. However, this alone won't create a mirror like finish.
Polish the floors using a polishing pad attached to a floor buffer. This will bring out the luster in the marble.