best bet is to use a product like Johnsons floor maintainer, I get it fron Greenhams. hot mop the floor after sweeping and buff with a red pad on a numatic and finish with a fresh coat of seal and a tan or white pad and a spray buff. that should produce stunning results if the original surface is sound........ If not you will have to sand back and hoover to remove dust, then damp mop, leave to air dry and then drop at least three coats of seal allow at least an hour between coats, then buff to shine and walk away with a smile.
To keep good condition after that just, :
damp mop at least weekly after a sweep and buff once every two weeks depending on traffic. Good Luck.