I have a clicker just never done anything with it. When do you click? The wanted behavior or the unwanted? I have tried to refocuse him with treats and I guess my treats didn't make the cut. Do you use an extra special treat?
When behavior of any kind starts, DON't yell "bad" or "no" and click...just click (grabs immediate attention) and say in your mom voice "sit" and then "look at me" and point to your forehead or hold a little treat there. Once you get the focused look, say "good boy/girl" in your happy voice and give the treat. You may have to work up to "Sit" and "look at me". That's why I suggest practicing not just on walks but at home too.
Little Evil sees the clicker in my hand she comes and sits in front of me and starts looking for a treat on my forehead.
I use kibbles that she likes or the fruitables that Peppers Pet Pantry carries. Small, quick bite and low calorie.