I think jackie's advice is great. aside from being the "alpha dog" part. I learned that kenji was very VERY aggressive. He was neutered after being a year old, and being the male of him and I. We live in an apartment and he hadn't been socialized very much so he has the need to protect me from mostly everyone he doesn't familiarize himself with or feel "safe" around. I read a lot of books about punishment... I don't hit my dog. I use the old traiditional way of other alpha dogs in a pack. The alpha dog does not "hit" like a human. Instead, they pounce on them and put them on their back. For you, just pick up your dog as soon as you see something he is doing as disobedience, and lay him on his back putting very little pressure (like friendly patting but constant pressure) with one hand on his neck and chest... the other hand is creadling his neck and back during the flip. The alpha dog in every pack will "pin" the other dog down to teach him who's boss. they bite the neck and put them on their belly. Instead... gently pick up your pooch immediately after the deed,put him on his back gently and say "no". your hands should be placed GENTLY on their chest and neck (your hand an "L" figure with thumb outstanding) to put soft pressure on their chest when laid on their back. The trick is to pick them up and flip them on their back GENTLY. Your other hand is cradling their head and neck so you don't bump their head... you need to do this on a soft surface anyway. I'm used to it so i flip him over wherever he is bad. You just gotta get the feel of flipping him over. Practice on the bed if he ever starts biting. The "turtle" position is submissive and they will usually stop barking or assume your position as alpha in command.