From Real Simple magazine:

Mix 1/4 cup vinegar in a 16-ounce spray bottle with 1 drop of
dish soap and warm water. Spray the floor one section at a time and wipe
with a damp microfiber mop as you go. For periodic deep cleans, use a steam cleaner
to clean both tile and grout—the steam does the work of removing stains
(and bacteria!).