An Alpha Dog is a dog that thinks he is the boss. You need to teach him that the opposite is true.
As alpha dogs are very sensitive to body language, using your body language is the best way to train them. If you are displaying body behaviors that confuse him then he is not going to be able to read your ,position, and decide that you incompetent. He will then try and take over your position as master.
Oddly, many behaviorists believe that most dogs actually dislike the position of alpha dog, but take it on as a necessity when they see you being weak. Most dogs would prefer to be a dog lower on the social rung where life is more secure, well defined and easier. So part of your dog’s aggression might be due to the fact that he is irritable at having to take on the task of doing your job as the master.
To get your dog to respect you, you are going to adopt body language that will impress him. You need to have a confident posture, a dignity and a calm. This is why emotionally ill, mentally ill or people with addictions often end up with an alpha dog The dog picks up on the addict or mentally ill person’s insecurity, inconsistency and inability to communication. Dogs can sense such problems as low self-esteem and will ignore the commands of someone who is uncooperative.
If you need your dog to be submissive, (but not too submissive) you need to have good posture and the ability to make meaningful eye contact with the animal. You should speak to him in a normal voice and never lose your temper. You should never stoop to use baby talk or your dog will never learn. You should also never beg your dog to do something. Dogs respect personalities that are a bit tough but still calm in tone.
With most dogs, just this change in your attitude and an obedience course will be enough to train an alpha dog. However if the dog has already been allowed to get away with growling or biting, then he might not give up his alpha position that easy. Usually your assertion that you are the leader of the pack can cause your dog to act more aggressively then before. This is where you might need a trainer.
If you decide to train the dog yourself, keep in mind that you are the same owner who trained your dog to be the alpha dog in the first place. Don’t try the same thing twice and then expecting a different outcome. If your dog is jumping, biting or snapping and snarling at strangers your first responsibility is to put a muzzle on the dog until you figure out what the problem is. Also you must always keep the dog on a leash. If you own a dog that displays aggression, then take out liability insurance. Your dog is out of control and unpredictable.