"Insanity: doing the same thing over and over again and expecting different results." --Albert Einstein
"Practice does not make perfect. Only perfect practice makes perfect." --Vince Lombardi
"We are what we repeatedly do. Excellence, then, is not an act but a habit." -- Aristotle
I want to talk a little bit about something that i think separates a good sheepdog trainer from a bad one, a quality that i think some people bring to this that makes them a "natural" at it. And that is the ability to try something, evaluate if it's working, and if it's not, to try something else. A sheepdog trainer has got to be flexible in his or her approach to training. If something isn't working, try something else! The handler is supposed to be the member of the team with the bigger brain. There's nothing that makes me cringe more than to watch a novice trainer making his dog do something wrong over and over and over, hoping that it'll get better. (See the Einstein quote above.) All you are doing is practicing failure, perfecting your failed attempts and firmly establishing a bad habit.
When my Jet dog was young and first in training, i was working with a trainer who really wanted me to get her bringing sheep out of tight corner properly. It made him crazy that she couldn't master it and he wanted me to keep drilling at it until she got it. She'd start into the corner but was uncomfortable with the tight space, and her eye would kick in making her want to cut back around the wrong way when the sheep would try to come out of the corner. So i went home and did some thinking about my young dog, who looked to be a talented girl with a little eye, was a little softer natured, and wanted so much to please me. And i decided i didn't want to bully this dog into doing something she clearly wasn't comfortable doing. I don't want that kind of relationship with my dogs, and especially didn't want to break the trust with this dog that was already trying so hard to be right. And i didn't want to keep hammering away on that corner work, having her doing it wrong repeatedly, and practicing failure. Being the (supposedly) bigger brained member of the team, i stopped to think about the skills she'd need to handle pulling stroppy sheep out of corners - a good flank with a nice shape and speed, confidence to pull up right in that corner to push the sheep out rather than flying through, etc - and i went and worked on the skills in an easier situation (open field), and practiced success. Next i took her into easier corner situations (easier sheep, a more open corner, etc.) and again practiced success. And when she had the skills to handle the tougher situation, we went back to it and she handled it beautifully, without a hitch, because the habit of doing it successfully was firmly set with her.
When you go out to train your dog, try to pay attention to what he's doing wrong, and try to figure out ways to help him be right, to set good habits. Unless you're intentionally allowing something to be wrong (see the article on Trading Problems), you should be trying to help your dog be right, and practicing perfection/success. I'm not saying your dog has to be 100% perfect all the time, but if your dog has a particular problem, you should be finding ways to help that dog be a little more correct all the time, and working your way towards perfection, rather than doing something wrong over and over and getting that wrong action firmly set in the dog's mind as "okay".