Sand the edges of the cracks using fine-grit sandpaper, which will remove any sharp edges or roughness.
Brush off the cracks using a 2-inch round paintbrush to remove any debris.
Apply paper tape across the cracks, keeping the paper tape smooth and taut. Cover the cracks completely.
Spread spackling compound over the tape-covered cracks using a trowel, then scrape the trowel across the wall to create a smooth layer of spackle that is flush with the wall. Allow the spackling compound to dry for eight hours.
Sand the dried spackle lightly using the fine-grit sandpaper to make the spackle smooth.
Fill a paint tray with latex wall paint, then apply the paint over the cracked area using a 3-inch flat paintbrush.
Coat a paint roller in the wall paint, then apply the paint over the entire wall to allow the spackled area to blend in perfectly with the rest of the wall. Allow the paint to dry for 12 to 18 hours.