Dogs exhibit poor behavior usually because of poor breeding or more commonly, because they are not well integrated into a family and not regularly exercised and stimulated. Before trying to conquer the barking issue, please consider how you might change or adopt a vigorous exercise and basic obedience program.
It is usually helpful to ask yourself what you want the dog to START doing rather than ask yourself what you want the dog to STOP doing. So for example, you might say I want the dog to stop barking when people come to the door. Instead ask what DO you want the dog to do when someone comes to the door. The answer may be something like; I want the dog to go to its place by the window and sit down. Can you see how this perspective might open new opportunities for you in re-conditioning your best friend?
Now we need to perfect the "sit" command. Your dog should practice sitting at home alone, then with others around. Then outside, on walks, in the park, when people approach, when people walk by the house, when other dogs walk by at a distance and then when they (the other dogs) are closer etc, at an outdoor concert, Home Depot and more, until your dog always sits on command. This is where many people have a problem they don't even know they have. They think their dog can sit, but it only happens at home in the living room when nothing else is going on.
Next, say "go to your spot" and lead the dog to its spot (let's pretend the dog has a day bed by the front window.) When the dog is on the bed reward it tell it to stay and do it again. Now we want to say "go to your spot" and "sit" before we open the door. Do this over and over again and make sure the dog is set up for success by doing it with people the dog knows such as family members that walk out the door and come back in right away. At first, let the dog know what's going on by having a spouse or child walk out the door, then tell the dog to go to its spot and sit. Make sure the dog will "stay" and then have the person walk in the door without ringing or knocking. If the dog stays, casually walk to the dog and reward it. After numerous successes, start knocking and ringing. Don't get too far ahead of yourself and do not reward or punish bad behavior. Wait and work on successes. Keep practice sessions short (5-7 minutes).
