It's important, according to me, to train in small doses so as to not lose the joy of playing chess. I personally think too many coaching and training classes may take away a child's interest in the game itself. The essential thing to do is practise often and, in case of a doubt, to consult a trainer.
Parents, first and foremost, it is important to... understand and recognise the activities your child is naturally gravitating towards. It's important also to ensure that your child likes what he or she is doing. I believe in exposing children to as many hobbies and extracurricular activities as possible.