My 4 month old tibetan terrier girl puppy barks at strangers...please help..?

My dogs also barks at strangers, but its more at night time which I really don't mind. The other night princess started barking a lot. Well it seem there was 2 unknown people out side my house door being extremely loud. So anyways. Take her out for walks on a leash. As cesar millan does, overy time she start to bark or even when she give u a sign, pull on her leash so she forgets what she was about to do. Also remember to be calm n relaxed when walking ur dog.