I've been trying to teach Lok a "line out" (walk to the end of the skijor line, pull it tight, and stand-stay) for ages. I've tried shaping, I've tried luring. Nothing has worked. So finally I decided to try targeting. I put a square of duct tape on the wall and planned to teach Lok to walk to the target and put his nose on it. So, everything was going fine, except that due to other training we've done, Lok kept wanting to target the wall with a paw before targeting it with his nose. I worked on eliminating the paw touch for like three days. I tried clicking only when he touched it with his nose, but he would still occasionally use a paw. And sometimes, he used a paw and then a couple seconds later he used his nose--so do I click that or don't I? In any case, it wasn't working. My timing was off, it was too hard to isolate the behavior I wanted.
Then, it dawned on me! I stopped worrying about the nose touch and started clicking him just for standing in front of the wall with all four feet on the ground. After just a few clicks for that, he got it! And it was one of those "OH! You want me to keep my feet on the ground! Why didn't you just say that in the first place?" moments that are so fun. Then we added the nose touch back in and it's been perfect ever since! I love lightbulb moments!