Turn off power to any outlets or switches near the damaged area
Remove loose drywall, plaster, or debris from the hole
Cut the hole into a neat square or rectangle
Measure the opening
Cut a drywall patch to fit the opening
Install backing strips or a wood support behind the hole if needed
Screw the backing strips in place
Fit the patch into the opening
Screw the patch to the backing strips
Apply drywall tape over the seams
Cover the seams with joint compound
Let the compound dry completely
Sand the area smooth
Apply a second and third coat of joint compound if needed
Sand again after each coat dries
Prime the repaired area
Paint to match the wall
Reinstall any trim, outlet covers, or fixtures removed earlier