Vacuum the entire ceiling area with a dusting brush or similar attachment to remove cobwebs, dust and dirt from your ceiling and reveal its true color beneath any grime.
Lay a dropcloth over the floor and any furniture or decor items in the room. If the spot you are repairing is near a wall, use masking tape to hang a dropcloth over the wall so no spatter will affect the paint there.
Set a ladder in a position where you can comfortably reach the ceiling and paint a coat of primer onto the affected area with a paintbrush. Allow the primer to dry for at least 24 hours.
Put on protective clothing, including a long-sleeved shirt, gloves, eye protection and a mask. A respirator mask is best, as inhaling high concentrations of the spray material can be potentially harmful. Toxicity may vary by brand, so consult your container of spray texture paint for appropriate safety measures. Gloves may be any nonporous type, as long as they protect your skin from direct exposure to the product, which can cause skin irriation.
Climb the ladder and spray the area of the ceiling that needs repair, using a short sweeping motion unless the product packaging indicates otherwise. Cover the affected area and about 6 inches beyond it in each direction, lightening up the spray as you move away from the area that needs texture by pulling the can farther away. You may want to practice on a piece of cardboard first.
Blot away any excess texture with a sponge by pressing the sponge into the wet paint and then blotting out the excess paint using a stamping gesture as you move across the ceiling away from the wet area. Blot around all edges of the new texture to help blend the paint as well. Be sure to use a pressing or stamping motion, rather than a wiping motion.
Add another layer of texture using the same process if the texture appears too light in comparison with the rest of the ceiling once it is dry.