maybe you could try one of the anti pull harnesses that use the thick "strings" that go under their arm pits? they work well for my hubby when he walks caine. also, they have things that go on your leash and when it pulls it puts out a really high pitched whistle that we can't hear but your dog can, and maybe it'd keep him from pulling. also, you may want to try using whatever you usually do and randomly change directions that way your pup learns he needs to pay attention to YOU and where you will want to go next. also helps, but more time consuming if you just stop and make him sit stay every time he pulls, even the least bit. that one takes a while longer and a lot more patients but it does work eventually.