Hammer crown molding around the top of the cabinet and the ceiling. Miter the joints of the crown molding so that it fits perfectly around the contours of the prefabricated cabinets. Caulk the edges of the molding for a more impressive look.
Repeat the process with baseboard molding around the base of the cabinet.
Paint or stain the molding to match the cabinets.
Miter the ends of 1-inch wide pieces of molding and arrange the pieces in rectangular shapes on the cabinet doors. This will make the doors look recessed and carved. Repeat the process on any visible sides of the cabinet.
Hammer filler strips of wood in any gaps between the prefab cabinets.
Paint or stain the wood to match the cabinets.