I have social anxiety and i'm also a parent to a child who has adhd and social communication issues. In regards to what should be taught,it depends on the age of the child and the nature of the condition. In general,mindfulness,assertiveness and self confidence building would be really useful. I know in my own life experiences assertiveness and self confidence would've really helped me. Social skills would also be useful.
I attened a workship earlier this week which was to do with neurofeedback and diet and nutrition. I personally didn't find the neurofeedback section very useful however we had a speaker come in to do a presentation on how what we eat or even don't get enough of in our diets can make issues such as anxiety,depression,sleep deprivation a lot worse and harder to manage effectively. They have a website which might be worth a look just to get an idea of the kind of thing that I mean
www.foodforthebrain.org. I think this is something worth raising.
Also on another note,I know from my own experience and from speaking to other parents with children with a mental health condition,that people don't always know where to go for help. I feel it would be a good thing to have some kind of pamphlet/leaflet to make people aware of what support there is in a particular area,just something with telephone numbers and addresses on.