I recently punched a hole in this wall while removing the backsplash of a countertop. But fixing it is actually easier than it may seem.
First, I cut a rectangular drywall patch and place it over the damaged area, tracing around it with a felt pen. Next, I cut out the shape with a drywall saw. Now, I'm ready to employ my special wall patching tool. A balloon. Boy, this is going to be a tough one to try.
The balloon will act as a clamp for this piece of drywall which I call a backer board. I apply some glue to the front surface, insert the balloon into the hole and then press the backer board against the balloon. The balloon pushes back, forcing the piece of drywall against the backside of the wall and holding it in place while the glue dries.
Next, I apply some glue to the drywall patch that I used as a template for the opening and press it firmly onto the backer board. Finally, I cover the seams with joint compound and paper tape. I'll let it dry a few hours, sand it smooth and apply a second coat.
So remember, if you have to do a repair like this, the perfect tool might not be in your toolbox, it might be in your child's toy box.