Dampen a cloth with isopropyl alcohol and rub it against the back and sides of your couch. This helps clean up any dust or dirt caught in the leather. Since these parts of the couch experience little stress, exerting great labor is unnecessary.
Remove all the seating cushions and dampen a cloth with some leather preparation solution. Spread the solution on the cushions with your cloth. This removes most of the old finish from your leather and prepares it for a new one. Continue to rub the cloth until the old finish begins to disappear.
Wipe the cushions down with a clean cloth dampened with isopropyl alcohol.
Dampen a small sponge with some light leather filler and spread it around. Leave the filler to harden after about 30 minutes. After it dries, wipe a piece of 1200-grit sandpaper around the cushion to remove any excess filter.
Dampen another sponge with leather repair compound and spread it around like you spread around the light filler. Allow it to dry for 30 minutes, then once again use another piece of 1200-grit sandpaper to remove the excess.
Shake your bottle with leather colorant for about 30 seconds to enrich the blend, then apply some to a clean sponge. Apply the colorant lightly on the cushion with this sponge. Do not press down too hard; otherwise, you will end up having to clean up the foam that builds up from the sponge on the cushion. You may apply another coat of the colorant after an hour to enhance your finish. Allow the couch to dry over the course of a day before you use it again.