The key to training dogs is consistency.
Since you are essentially teaching your dog a new language, you need to be patient with the learning process, and consistent with the training regiment.
Dogs need to know what the limits are and what behaviors are appropriate and accepted. When setting the ground rules make sure you have a clear set of do’s and don’ts. Your dog is willing to please IF he can figure out what he should and shouldn’t do.
For instance, if your dog is expected to sit before a mealtime, ensure that he always does so and he’ll soon learn that this is an expected behavior.