I used Water Dog by Richard Wolters. I always get compliments on how well trained and well behaved my dog is and a lot of that comes with age. One thing that I can't stress enough (no matter which training method you choose) is that the more time you put in with the dog the better your results will be, also the deeper your bond will be. Just repeat drills until you think it is enough, then do it 10-20 more times. Also, even once the dog has the basics mastered you need to re-emphasize them frequently. I found that when Kate was younger she would push me just to see how much she could get away with. She still does on the "heal", but I think that is mainly because when we are in the field most of the time now I just give her free reign so that she can enjoy herself. Plus, it just takes one harsh, "KATE!" and she is 10 inches off of my left side with me stride for stride.

That is just my 2 cents, though. Good luck.