You have to be consistant in correcting them when they bark.
This is ongoing training and can take time to see results.
I would say a good several months before Buddy did not bark
over every little noise he heard.
When he saw a dog through the window and barked I would
talk to him nicely because this is a natural bark but when
the phone rang and he ran around the house like a mad man
I would correct him firmly. Today he does not bark unnecessarly.
It took time and patience because this breed loves to yap
Hang in there and don't give up. In time it will get better.
Good luck
Carol & Buddy