Establish a Barking Interrupter
The interrupter is a special sound that gives your dog something to do instead of barking.
Start this like you do so many other drills — by building value for the sound that you will use to interrupt barking. I like “shhhht.” Its short, unusual, and easy to use.
Say “shhht” then treat immediately. Do this 15-20 times with great treats in a number of locations — by the front door, in the car (parked of course!), and especially on your dog’s place by the door. Don’t ask for any behavior at this time.
Do several sets of this drill over a few days and DONT USE IT FOR BARKING YET!
Use a really high value treat. At the beginning of practicing this drill you deliver the treat immediately after making the shhhht sound. After that, every once in a while you delay the delivery of the treat for a few seconds — your dog should be focusing on you and quiet during this delay period.
After a few seconds or immediately, click/yes and treat for being quiet.
After you get good at this practice a couple of quiet knocks on the wall, then say shhht and treat if your dog is quiet. Click here for a great video by Emily Larlham (kikopup) on teaching your dog to be quiet at the door