Aggressive behaviour must be checked without delay. Your dog must understand that all the members of your family are dominant, including (and even especially) any children. Any good dog training tips will include information on controlling an aggressive dog. Take a look at the list of dog training tips on this site and on others.

So the top tip within dog training tips has to be Positive Reinforcement. Punishing mistakes or unwanted behaviour often only leads to a frightened and even confused dog. If you catch your dog in the act of doing something unwanted, a firm “No” will suffice. There’s no need for physical punishment, or even for shouting. Show her the correct behaviour, or wait for her to do it herself, then reward, reward, reward. For example, if your dog is jumping up on you, just say “No”, firmly, and turn your back on her. Then when she gets down, turn to her and reward. In the beginning you can reward with food treats, but as your dog gets older, your praise will be reward enough.