There is a lot that parents can do to help your children succeed at learning. One of the most important things you can do is help the child develop self-awareness. Ask him or her questions about how s/he learns best, and encourage him/her to try new methods. Find things that s/he is good at, whether that is sport, art, music, working with animals or cooking. Boost his/her self-esteem by creating opportunities for your child to shine at these activities. However, s/he will still need to work at school subjects, so do everything you can to encourage and support his/her practice out of class.
Accept that the child may become tired more quickly than others, and recognise potential stress triggers. Teach him/her to recognise these signs too, and to take action before the crisis point is reached.