Instructions
Before you approach a dog, try to get a feel for his temperament and state of mind by looking at his body language. Is his tail tucked? Is he backing away from your presence instead of moving toward you? Is some of the hair on his back standing up? These are all signs of fear, and can lead to an act of passive aggression if you get too close too quickly. Of course if he growls and lunges forward, you are dealing with an aggressive dog, and you should get some help if you absolutely need to get close to him.
Crouch down, and turn your body to the side. The idea here is to try and get the dog to approach you first. Crouching puts you down on his level. Turning your body sideways keeps you in a more submissive, nonthreatening posture.
Avoid looking the dog in the eye during these first few minutes as you are trying to approach him. Direct eye contact is very confrontational, and it will possibly cause an act of aggression in the dog if he feels threatened in any way. Look right over his head, or just to the left or right of him. This way you can keep him in your peripheral vision so you can monitor his movements.
Keep your voice calm and cheerful. While you are still in the crouched position, try to coax the dog toward you. Extend your hand, making sure that it never goes above the height of the dog's nose. Any movements or gestures above the nose put you in a dominant posture, and that may feel threatening to the dog. So do not try to pet the top of his head, or stand up and bend over him until you are certain he is ready.
After you have made contact, stay crouched on the floor until you feel the dog is relaxed and comfortable with you touching him. Avoid making any sudden movements or loud noises in these initial stages. Continue to keep your voice very calm and upbeat.
How to Approach a Dog
The most difficult part about the human/canine bond is trying to remember that dogs use a completely different language than we do. We cannot count on them to learn ours, so we must learn theirs. And that starts when you first approach a dog that you do not know anything about.