1. Do not let your dog make a big deal out of your arrival home. In fact, as the alpha leader of your family's "pack", you shouldn't even greet him or her for at least 15 minutes. If your dog jumps around and pesters you before that, squirt him with water pistol or shake a can filled with pebbles. This will startle him, and if done on a regular basis, calm him whenever you get home. He won't make such a big deal of your arrival, and thus learn that he can greet you without jumping. Follow the same technique for any visitors to your home. Do not introduce the dog to your visitors until after 15 minutes or longer.
3. Because they have been rewarded for this behavior in the past, whether purposely or unknowingly. Some owners may, at one point or another, allowed the dog to jump on them or on their furniture, welcoming their dog's enthusiasm to see them. Other owners inadvertently reward their dogs jumping, simply by doing something good--such as walking or feeding the dog--right after the dog has jumped. Even if they told off the dog for jumping, by providing the dog with a walk or with food, they make the dog connect these positive actions, with a not-so-positive action: jumping! The dog sees thing in a very simple, linear fashion: if he jumps, he'll get to go for a walk--or even better, he'll get fed!
Unless given a command to jump, a dog should never be allowed to jump on humans. A dog that jumps on humans of its own free will is a dog that does not respect the person it is jumping on. Even those cute little toy dogs should not be allowed to jump on people. While you may think it is cute, it is not cute to everyone else. Not only is it annoying to most people to have someone else's dog jump on them, it can also be dangerous. A jumping dog can knock people over, muddy their clothes, put runners in nylons and scratch the skin.
Start by teaching your puppy the word NO. Use that word only when she is doing something you do not like. You have to use the word NO in a loud, stern voice that is different from all other ways you communicate with her, so that she knows there is something wrong. You also have to catch her in the act that you don't like, so that it will associate the word NO with the action that she is doing. Be consistent, and follow your verbal command with a light smack or moving her to a time out spot.
Many puppies don’t know their strength. When they jump up and you wave your arms and try to push them off, they may think it’s a game and grabs and bite harder. Tell them it hurts the same way another puppy would, with a YELP! Lay it on thick, overact and cry and sob like the pup has done major damage. Some tough dogs get the message using this. For the out-of-control grabby, ambush type of dog play, give him a taste of his own medicine and SCREAM (very loud but very short), and fall over “dead.” Don’t move and don’t say anything. Play dead for at least 15 to 20 seconds. The shock value may be enough to send a permanent message that such games stop all interaction, plus they hurt you—and playing dogs aren’t interested in hurting you and won’t want you to cry.
Nobody likes to have a handful of groceries knocked out of their hand or get muddy paw prints on their new pants as they walk through their own front door, let alone someone else's front door. Jumping up can be a cute greeting when you have a small puppy or dog at home, but as time goes on, it can become quite annoying to you and your guests. Teaching your dog to calmly greet you and your guests, without jumping, will create a much more enjoyable environment to enter into after a long day at work or when receiving guests at home.
When a dog jumps on a human of its own free will, it is not "greeting" the human, it is asserting its dominance over the human; it is the dog communicating that it is alpha and/or wishes to own/control the human. A subordinate would never dream of running over and jumping on the alpha dog of the pack. Space is respect and lower members of the pack respect the higher members. If your dog jumps on humans, it does not respect them. Note: when a young puppy jumps on humans it is sometimes its attempt to reach one's face. Puppies need to be taught not to jump up on humans as this behavior will manifest into other meanings as the puppy grows up into an adult dog.