If you're bringing home a second dog, here are some tips from animal behaviour consultant Nirupa Rao
The first meeting between the dogs should be in a neutral area, i.e., not at your home as this is your first dog's territory. Any public space can be the meeting point. Request the caretaker of the new dog to bring him to the neutral area on a leash and do the same with your dog. Use a cheerful voice and remain calm, as dogs pick up behaviour cues from their humans.
Bring the dogs' favourite treats – if your dog likes cream cheese, give him a small quantity of it when he meets the new dog so that positive associations are formed. During introductions, it is better for the dogs not to focus on each other completely. Take them both for a brisk walk so they are distracted by other sights and smells, thereby reducing the stress of the first meeting. When the second dog is brought home, give them both treats again and continue to do this for the first few days every time the second dog enters the house.
After the second dog's entry into your family, the most important thing to do is to ensure that the first dog's routine is completely unchanged. The first dog must not feel that life has been disrupted by the arrival of the second. His sleeping area, feeding times and walking times must be strictly continued as earlier. Ensure that the second dog has his own sleeping place, toys, feeding bowl and walking schedule and that he is made to feel comfortable in his new environment. Neither should be allowed to eat from the other's food bowl, so as not to create feelings of rivalry. If rivalry arises due to any reason, raise your voice firmly and say ‘Stop' or ‘Don't move'. Reward them when they back off.
For the first two weeks after the arrival of your new dog, ensure that they are kept in different areas without access to each other if unsupervised, until they learn to cooperate with each other peacefully.