Show how you notice and appreciate your child’s endeavours by offering them sincere praise, which is appropriate to their age and stage of development.
Praise their efforts, even more so than their achievements, and be precise about what was good, e.g. “well done for sticking with that difficult sum until you worked it out”.
In this way your child will learn that there is merit in more then just success.
Try to avoid associating their value as a person with their activity or behaviour, e.g. “You’re a good boy for tying your lace” or “You’re a bold girl for not tidying your toys”.