You can teach your child to share by doing it yourself! Children imitate grown-ups and when you are generous they will want to be too. And when someone (whether it is your child or another person) shares with you, show them how happy it makes you feel that you have been thought about.
Children need to know how to express the gratitude that goes with sharing. Sometimes they don’t do this and the other person will be less reluctant to share next time. Saying thank you is all it takes.
It feels good to share mainly due to the joy the other person shows on receipt. Once your child is in the habit of sharing and seeing the happiness from the other person’s face they will want to continue to share.
Not sharing can be seen as mean and selfish. Chat to your child about the benefits of sharing and the feelings associated with it. Being a generous and sharing person can help with friendships and getting on in the world in general.