Here's an exercise to try with your child. Keep a tally of how many times you use your repetitive "good job" phrase while you're interacting with your child. It's actually easier and more noticeable when someone else tally's for you though. Then try replacing your "good job" comments with other phrases, if you have a hard time doing it, keep a list around that you can quickly glance at.
Utah PLAY Project Home Consultant
Early Childhood Intervention for Children with Autism