Train your dog to concentrate on you and your commands. Keep calm because your dog will know if you are tense or worried. You can carry a walk stick with you. Most of the time the sight of the stick is enough to keep other dogs away. Don't use the stick to strike another dog unless they attack. A bright flashlight shined in the other dog's eyes is a deterrent. Carry an air horn or something that make a loud noise to scare the other dog off. Have a spray bottle with you filled with plain water or citronella spray can.They won't hurt the loose dog, but will startle it enough to run away. Always check if the dog's owner is close by and ask them politely to remove their dog. If the problem persists, call your local animal control and report the loose dogs, giving as much information as to location and description of the dogs.