From the dogs point of view
Have you ever stopped to think of the many variables and aspects involved in training your dog? Better still if we stop, stand back and take a look at some more simple things like what your dog sees, what your dog smells and the effect that the environment has on your dogs ability to process information and learn we could really improve learning for the dog.
I have considered the notion of having some dog owners who come to class sit on the ground and look up at a handler and then have the handler only pay them when they perform a certain exercise. I have definitely considered this notion when arguing against electric shock collars. I feel the best way to do this and prove my point about +P and e-collars would be to put an e-collar onto a person, don't tell them what you want them to do and shock them everytime they get it wrong. Once they get it right stop shocking them. I figure they wouldn't last even 30 seconds!
Anyway getting back to to original point of seeing things from your dogs point of view. Think about what your dog sees as you stand over them. Think about your hand position, your luring and how effective you are at the skill of luring. How is your timing? Think about it from your dogs point of view and what you are asking them to do with their body. Are you hanging back a little too long before rewarding when teaching something new? And what about when the behaviour does not present? Are you are getting frustrated while teaching a new behaviour? Frequently the behaviour does not happen because we either move things forward too fast OR we have changed something significant during the learning phase.
So next time your dog is looking a little clueless maybe actually put yourself in his paws for a few seconds, it may just be what you need.