Any existing pets and your new arrival should be vaccinated for rabies, distemper, parvo, and other common diseases, as recommended by your vet. The bordatella (kennel cough) vaccine may also be recommended for dogs. There is a good chance that your new pet could be harboring a disease, and it isn’t wise to unnecessarily risk your other pets’ health. It would be ideal to keep incoming animals separate from your own pets for a period of time if you have the space to do so (and this is a must if you are introducing a dog that haven’t been fully vetted), but this isn’t always realistic since the animal will be living in your home as a member of the family.
In the case of dogs, make sure you have a well-fitted collar and ID tag. Remember that this dog doesn’t know you yet and might get spooked and run. Take all possible precautions. Better safe than sorry!
You will have to treat the new arrival like a puppy (or kitten!) at first. Puppy proof the house before he arrives. If he is young or has not been raised in a house, he might be destructive and not housetrained. You should set up a crate for him with bedding that can be easily cleaned or thrown away if soiled or chewed (like old towels).
If you choose not to use a crate, you should have a small, pet-safe room (like a laundry room) for when you cannot watch them. If you use an outdoor kennel for unsupervised time, make sure it is very secure (a cover or top is recommended) and be sure to provide appropriate shelter, shade, bedding, and clean water. Please also remember that cats like to be outside more than inside.