You cannot give or praise your children into having good self-esteem. You can, however, support them in a loving, positive way while they find their own path to those good feelings about their own abilities and character.
I hope you are enjoying seeing little Billy run around the field with his little soccer ball. I noticed one thing, though; you seem to have a lot to say, whether it's to me, the other parents, or the coaches. I kindly request that you shut your trap.