Your first grader's self-esteem is directly tied to his performance in school and around other adults. After all, he gets a huge boost from a happy teacher when he nails a spelling word and you probably offer plenty of praise when he scores the winning goal on the soccer field. He feels good when he's the best and therefore adopts a must-win attitude. While it's perfectly fine to praise, make sure you're specific about the kudos. Instead of giving a high five for being the "best," compliment your child on his good sportsmanship, extra study time and perfect printing instead.