Whether it is a small nail hole or a larger hole, maybe the size of a door knob or a fist, repairing a hole in drywall can be done easily with some spackling putty, a little paint and possibly an aluminum wall repair patch.
Step 1: Brush away any loose debris and run a putty knife over the hole to press down any protruding edges. Wash the area with a non-residual cleaner such as TSP or Dirtex. Let the surface dry completely before proceeding.
Step 2: Holes less than a quarter of an inch in diameter or cracks less than an eighth of an inch in diameter can be patched with spackling putty. Use a small putty knife to scoop some spackling putty out of its container and press the putty into the hole.
Step 3: Overfill the hole with spackling. Hold the putty knife at a 90-degree angle above the hole. Slide the knife down over the hole, scraping away the excess putty. If a divot appears in the center of the patch, add additional spackling and scrape the hole once again with the putty knife.
Step 4: Use a damp cloth to wipe away any excess putty around the hole and allow the patch to dry.
Step 5: For holes and cracks less than 1 inch in diameter, prepare the area as before, and spread spackling inside and around the hole. Cover the hole with a piece of fiberglass jointing tape and spread spackling putty over the tape.
Step 6: For larger holes, use an aluminum wall patch to cover the hole before patching. Trim the patch so it is approximately 1 inch larger than the hole. Apply a thin layer of spackling putty to the surface around the hole. Press the patch into place and use a wide putty knife to smooth a thin layer of spackling evenly over the surface of the patch.
Step 7: Feather the spackling out along the edges to blend it in with the surrounding surface.
Step 8: Once the spackling is dry, sand the patched area with 100 grit sandpaper. Apply a second coat of spackling putty and let it dry.
Step 9: Lightly sand the area until it is smooth. Wash the surface with TSP or Dirtex to remove any dust particles. Wait several hours or even a day before priming and then painting the repaired area.