The child's parents can help by interviewing their child and submitting to the coach their and their child's goals for the season. The head coach may now have something to work with. Well planned and executed practice does. Diagrams and test procedures are now available at the above links. Create methodical systems of providing feedback.
Most kids see better than adults, and they know the ball went out, over, or too much to the left.
That was quite obvious. They need us to tell them why it happened and what can they do to correct their actions. Create team and individual evaluation charts. You may jolt down as many goals as you wish. Just be sure to prioretise goals and work plans.