Shaping involves the use of positive reinforcement to teach a desired behavior. A desired behavior is broken down into baby steps and your child is taught one step at a time. You praise and/or reward him for his attempts and his small successes towards the behavior. Shaping uses only positive reinforcement. No negative reinforcement or punishment is used.
Keep expectations small until step one is achieved. Praise effort as well as success. When step one is mastered, step two is taught and reinforced until success is consistently achieved. The third step is added, then the fourth, etc., until the entire behavior is achieved. Once your child can do the entire behavior, he is prompted each step of the way as he performs the behavior. As he demonstrates consistent success in the behavior, your prompts are given less often in a process called fading. Eventually your child will be able to do the entire behavior with only a prompt to start it.
If the behavior needs to take place in more than one setting, once your child has mastered the skill in one setting, he is then asked to perform the behavior in a second setting, a process called generalization.