Try putting her up on a chair or stool. Most puppies are so small when you say down, they just
look down, not go down b/c they are already so close to the floor. So put her up on a chair and sit. Then lure her with the treat and go down past the level of the seat so that the treat is actually much lower than it would be if she were on the ground. She will have to go in a down position to get closer to the treat. As soon as her elbows touch the seat say good down and treat.
You may also want to check out Britster's thread in the training forum too, lots of tips for trick training.
http://www.yorkietalk.com/forums/tra...-progress.html