
Training all the way. Different dogs respond to different equipment - and some don't respond to it at all.
Of my lot, the older 3 all respond well to the halti harness (Soli best, but that is with a lot of training).
But River will not respond to anything. I've tried her on the halti harness; mekuti harness; one of those plain walking harnesses with the double d-ring at the top above the clip; the no-pull harness from PAH that deansami has described; halti headcollar; headcollar and harness combo; half-check collar; flat collar; basically every type, and none of them work.
The only thing that ahs worked to any degree with her is training - and that's working brilliantly. I've done one walk with her so far (our walks are all off-lead so training times are thin on the ground), with about half an hour of on-lead time, and she went from a steam-train puller to doing 35 continuous paces (my paces) by my side. For a dog that's been a steam-train for the 18 months I've had her and for the 14 months of her life before that, that's fantastic and shows the value of putting the work in.
Incidientally I'm using the 300 peck method with her - basically, take one step, if the dog doesn't pull, reward. Then two steps, reward. Three, reward. So on and so forth up to 300. If the dog pulls - back to one step, two, three and so on again. With River I've been rewarding any walking with a slack lead - not focusing specifically on having her walk next to me, that just followed naturally as she realised what I was after. I did a little bit of the same thing with Soli and it helped immensely, with her the headcollar/harness combo was particularly effective also (to my huge relief as she's one of those random lungy type dogs, and weighed 42kg when I first got her!).