we groom all our dogs ourselves, and I still groom shadow, but my mom tought me how to cut dogs hair, and as far as I know she only knows how from experiance, she used to breed and raise shelties, and had a puli once. she also does all the uman haircutting in my familiy lol and all my friends want her to cut their hair too because she actually listens to what you want done, and and does it perfectly every time I am not as good as she is yet, but I am pretty darn good at it for a 16 year old lol we dont use any books or anything, we lok at the dog, we think what would llook nice on that dog, we look at what that dog often does, and we suit that haircut to accomidate that.. for example Happy often runs into bushes and stuff so I keep her pants cut short, and her tail hair trimmed, I also keep the hair around her feet trimmed to prvent mud, and snow ball in her feet. with shadow, I cut her hair shorter then normal yesterday because she is not brished as often as she should be, she her pans are clipped short, the hair on her ears get trimmed short, and her ears shaped, and I trim the hair around her paws because they gather snowballs, and to much hair makes her look like she has 3 times as many toes lol then for the rest of her hair I just thin it out a bit. Blair, the back of his coat cords, he has no brow, and he gets hot very easily, so his head is trimmed shorter, his back end is kept clipped short, his front end a tiny bit longer than the back but not much, we also trim the hair on his back to hide his roach back.