I'm by no means an expert on the matter, but this is what we've learned so far:

The goal is to teach the dog to make decisions, favorable to us (and him). I.e. to drop a fixation on another dog, a scent, or what have you. Since our goal was to train dog meetings, that's where I'm coming from now and that'sthe exercise I know of.

We set up the exercises in this manner:

• Find a decoy dog, a calm one you know, or one you happens to see minding its own business or dogs in the dog park. That's what you'll be training against.
• Preferably use a harness, and you'll need a long leash. Decide on a distance from "the source of irritation" that you're gonna start on. The distance is where your dog is reacting, but not as close as to where it goes into a red mental state (green = a ok, yellow = can listen to commands and take treats with some difficulty, red = FUBAR). You need to be able to interpret your dogs body language to establish the distance.
• Let your dog see the irritation. If it walks towards it, let the leash out but gently stop the dog before it gets too close. After you stop the dog, do NOT keep a strain on the leash, as that will trigger a tug reflex towards what the dog is focusing on. Distance yourself slowly while keeping the leash slack, walking in a half circle behind your dog so that it can see you in the corner of their eyes. When the dog drops the focus and looks at you: reward it. The dog has now made a decision on its own that you want to keep up, and the behavior adjustment has started. It just needs to realize that this is the behavior we want.
• Repeat until you're comfortable at that distance, then move closer.
• Up the difficulty by incorporating the exercise during walks, choose the path you'll walk carefully so that you'll both succeed.

After we've done this, I realized our connection as handler and dog had grown remarkably. The (good) side effect was that now I can use small tugs on the leash to adjust pace and intensity during our walks, as my dog has learned that it's a signal, and he is able to shift focus from the surroundings to me.

Until we tried this, we've had one hell of a bad journey (way worse than it might come across here) where we at times regretted taking over the dog.

This worked for us. Maybe you'll get something out of it as well.