When you think your dog understands the meaning of good the next sequence of events should be giving the dog the command sit. The dog sits, you say good and then treat. Soon the dog learns that good is reinforcement all on its own. Now that you have the basics of training you are now ready to put it to use. That is a valid point and you should ignore whatever the dog does and try, try again.
Many people have expectations that are far beyond their dog.
You have to take small steps in order to work up to the overall behavior. All dogs benefit from taking a basic obedience class. Your local kennel club or humane society is a good place to start. An owner must remember that training is an ongoing process and doesn t stop at six or eight weeks of training. You and your dog must practice training skills so that neither of you get rusty on such skills.