Using a good quality feather duster, lightly go over the case to remove any gritty particles that could scratch the finish under the pressure of a dust cloth.
Polish the finish with a soft cloth (T-shirt or diaper).
To remove fingerprints, use warm water on a soft cloth.
Then dry with a seperate, soft dry cloth.
A mild solution of dishwashing soap (ie. Ivory), diluted in warm water will remove grease and oils from the case, and also will work on keytops.
DO NOT use ammonia products, waxes, polishes or woodfinish oils.
Call a professional cabinet repairman for scratches and dings.