I had the same problem with Zoey when she was little. First, use a harness - NO COLLAR. When they begin to pull you turn sharply and start walking the opposite direction - continue turning every time they begin to pull. You will give them a little jerk as you turn but they get the idea. This was shown to me by a dog trainer. It finally worked.
Cherie
__________________  RIP my darling little Gina |