Seal your marble floors with a stone sealer. All new marble floors should be sealed. Reapply sealant once a year. There is a wide range of sealant applications available. Apply the sealant according to the manufacturer's directions. Always test a tiny bit of the sealant in a hidden area to make sure it does not discolor the marble.
Clean your marble floors regularly. Use a cleaner with a neutral pH. Acidic cleaners such as lemon or vinegar-based cleaners can make the stone deteriorate. One part ammonia to five parts warm water is a good solution for cleaning. Clean the floors with a mop that is dampened, not soaked, with the solution. Too much water floating on the surface of the floor will stain your floor with water spots.
Dust mop your marble floors frequently to prevent dust and dirt from penetrating the stone and building up.
Clean any spills on the floor as soon as possible. Letting liquids rest on the surface of the floor (especially acidic drinks) can cause staining and deterioration.
Use rugs, carpets or rubber footings under furniture to prevent scratching.
Hire a professional floor finisher to periodically polish your floor. A professional will sand out scratches on the surface and use a stone polishing machine to bring back a mirror-like finish.