How old is the dog? If the dog is very old there may be nothing you can do. If it is still a puppy try letting the pup know just who is boss and teach it some discipline. You are the master of the dog train it the way you want it to act.
Obedience training and socialization is the best way. If the dog is past puppy stage than it will be more difficult because the dog is probably set in its ways but it can learn to be less agressive.
In treating dog aggression be advised that it depends on what type of aggression you dog has. I would seek advice from a professional dog handler. Good luck.
Your aggressive bull dog may be controlled accordingly with his age. Starve for few hours
Go for a walk and have a stick in your hand. Beat him if he does not obey orders.
