Your child won't win at everything. Therefore, you need to learn the art of being a good loser. From an early age, they should be taught to congratulate the winner and shake their opponent's hand. Talk to your child about winning and losing.
It is important that you understand that it is okay to lose and that it can help you be better next time. It is an opportunity to learn and be better in the future. They should congratulate the winner because one day they could be the winners and it would be nice if others congratulate them.
The world will be a better place when we all learn to rejoice in the successes of others, especially if those people are friends and family. By playing board games you can teach me by example. Congratulate the winners with your heart so that you feel good about the achievements. On the other hand, if someone loses you can tell them that they may have better luck next time and smile at them.
It's a way of teaching your child that these are the ways we show kindness to others, especially when we lose. It's a difficult lesson for younger children to understand, but you have to be consistent with your behavior and your insistence that they act the same way when they don't win. Eventually, in time this will pay off and you will have a child who has truly learned to be happy for others. because they know what it's like to be a winner and a loser, and they can't win all the time.
You can also take the opportunity to talk about what they did well in the game or what they did wrong and why they lost. Point out the good things and then ask them what they think they could improve next time. Allow them to think for themselves instead of telling you the answer because that way they will internalize more what to do.