Redirect with a sit command. The simple 'sit' command can be useful in many different situations. Most importantly, it is a great distraction technique for redirecting your dog's attention from an undesirable behavior, such as jumping up. When your dog jumps up on you, turn your back to them while keeping them in your peripheral vision. Ask her to sit and immediately praise her when she does so.
Why do dogs jump up? A plausible explanation arises from their ways of communicating with each other. A puppy greeting an adult dog often licks the adult’s muzzle -- a polite, deferential behavior. Dogs, of course, descend from wolves, among whom muzzle-licking is how pups get the grownups to regurgitate food for them. Domestic dogs rarely nourish puppies this way, but muzzle-licking has survived, maybe because deferential behaviors are handy for a social animal. Think of humans saying “No, after you.” Muzzle-licking is also an appeasement behavior -- something you trot out to de-escalate a fight. A human might lift up his hands, palms toward the person he’s arguing with.