Clean the wood with a slightly damp cloth to remove dust and grime from the surface. Excess water can cause swelling and damage to hardwood, so use water sparingly on the cloth.
Apply furniture oil to a clean, dry cloth. Rub the oil into the wood with long strokes, following the wood grain. Allow the oil to dry completely. Some oils such as linseed might take several days to fully dry.
Lightly sand the furniture with a fine-grit sandpaper if the surface is rough, and wipe with a damp cloth. Apply a second coat of oil, and allow it to dry completely. New, unfinished furniture might require several coats of oil to achieve the desired finish.