Trouble controlling big dog during walks?

Gentle leaders work very well. Its a harness that goes over the nose so when the dog starts to pull their nose gets turned toward you therefore making pulling impossible. The downside of a gentle leader is that inexperienced people think it is a muzzle on your dog and get scared your dog is aggressive. Note that this is not a permanent fix, your dog is still going to pull whenever he doesn't have it on. Use the gentle leader to aid in your training of the heel command! Train faithfully and in several weeks to a couple months you will have no need for the training tool!