Hank is 13 months old now and most company is suprised with how well he is doing. From early on I have made it a point to keep on him from the second someone comes over until they leave. I firmly tell him "off" and if he doesnt listen, I'll make him sit and hold him by the collar until he calms down. He is usually very good nowadays. I believe consistency and praise (when done right) is the key.