Great advice, "the look" command. I have 2 yorks and one "in training" and have trained 2 more . They are really smart dogs. They watch and look at your face all the time and your body language tells them far more than any words. Mine and their "cousins" (when they do sleep overs) all sit at the door when people come to it and "stay", "wait" at doors before they are opened and the basic polite things that help when people come and for basic safety. Ours get a long walk every day and that really helps with the energy leveling out. Having them sit and letting the other dogs come up helps when you have one that is very outgoing and in people's faces. Taking it on thru more obedience classes is the best idea of all. Sometimes I babysit as many as 9 dogs at one time so those basics are worth their weight in gold. One of the yorks follows all of the commands at my house but not at its own! Now that dog is as smart as most kids!
Stick with it and use your body more. That is the real communicator. By the way...are you hyper? If so, the dog may be reading that also. Glad you are working hard with the lucky pup.