The Gentle Leader Collar
When we first attempted to train our lab/shepherd mix, she was simply too excited and/or excitable to listen to us, even with a handful of string cheese and hot dogs. But once the Gentle Leader was recommended to us? She calmed right down and was able to sit, stay, heel, etc. No that we've kept up on her training (bad dog companion... bad), but when I want to take her for a walk, I can still count on the gentle leader to keep it to a walk instead of a drag.
I've tried walking my new dog with just the leash attached to the collar and then the leash attached to this Gentle Leader collar and she's definitely a lot easier to control with the Gentle Leader. She gets freaked out by squirrels and other dogs but with the GL it's easier to calm her down.