You click and reward any moment that you dog take focus on the other dog and you. Even if its a half look. Anytime something breaks his concentration, you mark it (click) and reward.
Before you even try the walk with other dogs, do this at your house. Anytime you call Ringer and he looks at you mark and treat. Do it all the time so he knows whatever you do when you call his name he is looking at you. Then take him into a setting with more distractions. Do that same. I use "LOOK" and when I do that, both my dogs look at me, I click and reward. If we are walking, and I see a possible distraction, I say "LOOK" they focus on me, I dont have to click anymore since they know it but when you are training, immediately click when they look at you, praise and keep walking.
It will take some time.
Before you even try the walk with other dogs, do this at your house. Anytime you call Ringer and he looks at you mark and treat. Do it all the time so he knows whatever you do when you call his name he is looking at you. Then take him into a setting with more distractions. Do that same. I use "LOOK" and when I do that, both my dogs look at me, I click and reward. If we are walking, and I see a possible distraction, I say "LOOK" they focus on me, I dont have to click anymore since they know it but when you are training, immediately click when they look at you, praise and keep walking.
It will take some time.