How do you prevent barking in puppy?

no tricks, just hard, consistent work. i recommend desensitizing your dog to sounds that could trigger barking (or fear for that matter), such as the doorbell, vaccum, fireworks, etc. - a Sound Socialization CD is very useful for this. also, you have to be mindful of NOT reinforcing the barking. so if the dog is barking for your attention, ignore her. finally, its helpful to teach some basic manners (recall, sit, down, etc.) and redirect your pup when she starts barking. i use a recall when mine start running outside to bark at passersby. hth!