Lest I be misunderstood, I want to make it clear that I'm not telling my kids they're bad at anything. I just remember being praised for everything I did and it didn't ring true because there were things I KNEW I wasn't talented at, and would never be talented at. So I am not telling my un-athletic daughter that she's not athletic. I'm just not heralding her as the next Mia Hamm. I certainly don't want to discourage her from trying sports.
Fidelia makes an excellent point, and that is what I have tried to do--emphasize their character over their abilities or lack thereof, and let them own the motivation to build superficial skills.