Obtain a bottle of natural oil that will not damage leather. Neatsfoot oil, mink oil and olive oil are all leather-safe and will have the added benefit of conditioning the leather, which prevents cracking.
Spray an even, light mist of the oil on the leather.
Smooth over the leather immediately with a sponge to ensure there are no spots but an even layer of oil.
Allow the leather to dry completely. These natural oils darken the leather, but only by a few shades at most. For drastic color change, opt for leather recoloring techniques using a leather dye.
Prep the surface of the leather by spraying on leather cleaner and wiping it away with a dry cloth.
Make sure the leather recoloring dye you purchase is darker than your couch's current color. Spray on the leather recoloring dye, and even out the layer by smoothing it with a dry cloth.
Wait one day before touching the couch to prevent smudges.
Rub leather conditioning cream into the surface of the couch to replenish lost moisture and prevent future cracking.