If your child has undue anxiety about his studies, his social interactions, or his health issues, consider tips from these free online articles to be sure you are not unintentionally encouraging anxious thinking:

• What to Do (and Not Do) When Children Are Anxious
• Anxious Kids: Are You Dealing with an Insecure Teen?

You might also work through some chapters in this book: Helping Your Anxious Child: A Step-by-Step Guide for Parents. The author takes a cognitive approach with topics like “Detective Thinking” to help the child detect (and allay) his own anxiety-inducing thoughts.

For older grammar school or middle-school students, it might be time to introduce a new “class,” perhaps  once a week, with written or oral exploration of these topics, No pressure, just curious discussion. If the student is not a strong reader, you could work through some of the chapters yourself, and then present one or two exercises that might apply.