How do you teach an old dog how to walk on a leash?

Go on a normal walk, just like you would any other day. Walk at a slow pace. If you run, or even jog, you are encouraging the dog to pull.

Whenever the dog starts to pull, immediately stop. Hold the leash firmly, but do not try and pull the dog back to you.

When your dog turns his head to look at you, give a hearty "GOOD DOGGIE!" then move forward and keep on walking. About every three or four times this happens, give the dog a treat. This is called yielding to the leash.

Do not try to take long walks with this method. Your dog will soon tire or get bored from this training.

WARNING: Be prepared to wait 5-10 minutes before your dog gives in and turns to look at you. I once had a 20 minute standoff before Dewey finally gave in!