One of the first items on our list to tackle, was the hole in the wall behind the doorknob. The previous owners patched the area up a couple times, and even added a plastic stop there, but we decided we could do better than that (IOW, the right way):
First, we cut out the patched up area completely. Then we kept cutting until we reached 2 studs.
Look at all the patch gunk we discovered!
Then we cut out a a piece of new drywall to insert into the hole. We screwed errr nailed* the new piece into the studs.
We then went over the seams with joint compound and sanded after it was dry.
Then primed, and 3 coats of paint, and problem solved!
*Our battery to the cordless drill is dead. This is making life around the house really difficult. We could use a sympathy drill...