I need some help with getting control of the puppy's barking. He is the type of dog that likes to bark at everything - friends coming in the door, the mailman, a squirrel out the window, etc. I don't mind him being a "watchdog" and alerting us to dangerous menaces like the neighbors and mailman , but I'd like to be able to tell him enough and have him stop barking. Any suggestions for teaching him to stop barking on command? He's very smart and is doing great with clicker training. He picks things up quickly and is very food motivated, which helps.