We has this with our 3 yr old. He was fine until we had new house built beside us. He would bark at anything, we actually nipped in the bid quiet quickly and were able to borrow a bark buster and only pop it on during the night.

It omits a high pitched noise that doesn't hurt the dog and is quick, so it breaks their attention. We like him to alert us at what's going on. So as soon as it sounded like he was settling, we turned it off. He still barks but he barks at things he is meant to.

It helps that he doesn't like upsetting mummy, he knows when I am displeased with him, by the tone in my voice, and I suppose my energy too. See if u can find some information on Cesar Milan the dog whisperer. The way he explains things makes things so much easier.