The key thing to keep in mind is that you want to practice away from work, the same way these kids practice away from the bright lights of a big game. Honing your skills and learning to execute at your best when it matters most is something that should become part of your every day experience.
Always trust in yourself, especially when starting something new... even while staring at a blank page, an empty new office, or a first meeting with venture capitalists. You can't score if you never take a shot, and even your misses end up being good practice for your next shot while you develop the ability to win.