Cut the damaged area into a clean square or rectangle
Remove loose drywall and debris
Measure the opening
Cut a drywall patch to fit the opening
Install wood backing strips inside the hole if needed
Screw the backing strips to the existing drywall
Place 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
Sand the dried compound smooth
Apply a second coat of joint compound if needed
Sand again after drying
Prime the repaired area
Paint to match the wall