Remove any dirt or dust from the couch using leather cleaner and a clean cloth, or shoe polish brush.
Wipe the area that is to be repaired with denatured alcohol. This will be included in your leather repair kit.
Using the spreading tool in your leather repair kit, spread a thin layer of repair compound over the cracked area, and overlapping 1/2 inch into the surrounding leather. Try to apply the repair compound as smoothly as possible. Dampen your fingertip with water and gently smooth rough edges, if necessary. Let the repair compound dry completely, usually within 30 minutes.
Examine the repaired area. If the crack is not filled completely, or the repair looks unfinished, repeat the process in step 3. It typically takes between two and five applications of repair compound to completely fill the cracks.
Sand any rough patches very gently with 600 grit sandpaper. This should be included in the leather repair kit.
Apply leather dye in the appropriate color for your furniture. Paint on in thin layers, using the sponge applicator in the repair kit. Allow to dry for at least 15 minutes between each coat of color. Continue applying thin coats of color until the repaired area matches the rest of the couch, and color is even. After applying the final coat of color, allow to dry for 24 hours.
Treat the entire piece of furniture with leather conditioner. For continued maintenance, and the best care of your leather furniture, dust weekly, and apply leather conditioner every three months.