There is a lot of advice available, I found this article by Dr Clark Goldstein a child and adolescent psychologist who specializes in the treatment of mood and anxiety disorders particularly sensible and practical, I hope you do too.
What to Do (and Not Do) When Children Are Anxious
How to respect feelings without empowering fears
Dr Clark Goldstein, PhD
When children are chronically anxious, even the most well-meaning parents can fall into a negative cycle and, not wanting a child to suffer, actually exacerbate the youngster’s anxiety. It happens when parents, anticipating a child’s fears, try to protect her from them. Here are pointers for helping children escape the cycle of anxiety.
1. The goal isn’t to eliminate anxiety, but to help a child manage it.
None of us wants to see a child unhappy, but the best way to help kids overcome anxiety isn’t to try to remove stressors that trigger it. It’s to help them learn to tolerate their anxiety and function as well as they can, even when they’re anxious. And as a byproduct of that, the anxiety will decrease or fall away over time.
2. Don’t avoid things just because they make a child anxious.
Helping children avoid the things they are afraid of will make them feel better in the short term, but it reinforces the anxiety over the long run. If a child in an uncomfortable situation gets upset, starts to cry—not to be manipulative, but just because that’s how she feels—and her parents whisk her out of there, or remove the thing she’s afraid of, she’s learned that coping mechanism, and that cycle has the potential to repeat itself.
3. Express positive—but realistic—expectations.
You can’t promise a child that her fears are unrealistic—that she won’t fail a test, that she’ll have fun ice skating, or that another child won’t laugh at her during show & tell. But you can express confidence that she’s going to be okay, she will be able to manage it, and that, as she faces her fears, the anxiety level will drop over time. This gives her confidence that your expectations are realistic, and that you’re not going to ask her to do something she can’t handle.
4. Respect her feelings, but don’t empower them.
It’s important to understand that validation doesn’t always mean agreement. So if a child is terrified about going to the doctor because she’s due for a shot, you don’t want to belittle her fears, but you also don’t want to amplify them. You want to listen and be empathetic, help her understand what she’s anxious about, and encourage her to feel that she can face her fears. The message you want to send is, “I know you’re scared, and that’s okay, and I’m here, and I’m going to help you get through this.”
5. Don’t ask leading questions.
Encourage your child to talk about her feelings, but try not to ask leading questions— “Are you anxious about the big test? Are you worried about the science fair?” To avoid feeding the cycle of anxiety, just ask open-ended questions: “How are you feeling about the science fair?”
6. Don’t reinforce the child’s fears.
What you don’t want to do is be saying, with your tone of voice or body language: “Maybe this is something that you should be afraid of.” Let’s say a child has had a negative experience with a dog. Next time she’s around a dog, you might be anxious about how she will respond, and you might unintentionally send a message that she should, indeed, be worried.
7. Encourage the child to tolerate her anxiety.
Let your child know that you appreciate the work it takes to tolerate anxiety in order to do what she wants or needs to do. It’s really encouraging her to engage in life and to let the anxiety take its natural curve. We call it the “habituation curve”—it will drop over time as she continues to have contact with the stressor. It might not drop to zero, it might not drop as quickly as you would like, but that’s how we get over our fears.
8. Try to keep the anticipatory period short.
When we’re afraid of something, the hardest time is really before we do it. So another rule of thumb for parents is to really try to eliminate or reduce the anticipatory period. If a child is nervous about going to a doctor’s appointment, you don’t want to launch into a discussion about it two hours before you go; that’s likely to get your child more keyed up. So just try to shorten that period to a minimum.
9. Think things through with the child.
Sometimes it helps to talk through what would happen if a child's fear came true—how would she handle it? A child who's anxious about separating from her parents might worry about what would happen if they didn't come to pick her up. So we talk about that. If your mum doesn't come at the end of soccer practice, what would you do? "Well, I would tell the coach my mum's not here." And what do you think the coach would do? "Well, he would call my mum. Or he would wait with me." A child who's afraid that a stranger might be sent to pick her up can have a code word from her parents that anyone they sent would know. For some kids, having a plan can reduce the uncertainty in a healthy, effective way.
10. Try to model healthy ways of handling anxiety.
There are multiple ways you can help kids handle anxiety by letting them see how you cope with anxiety yourself. Kids are perceptive, and they’re going to take it in if you keep complaining on the phone to a friend that you can’t handle the stress or the anxiety. I’m not saying to pretend that you don’t have stress and anxiety, but let kids hear or see you managing it calmly, tolerating it, feeling good about getting through it.
Source: The Child Mind Institute, Author: Dr. Clark Goldstein - a child and adolescent psychologist who specialises in the treatment of anxiety and mood disorders.