Don't be afraid of failure. Or be afraid, but take the leap anyway.
Whatever happens, you'll learn something. You'll grow. And you'll have a little more courage to go with in the next run, knowing failure isn't the finish line. It's just one of those obstacles that might get you dirty and bruised.
And then find the next challenge. The next big project. Until you have enough calluses to not be afraid anymore.
I'm not there yet, and I'm not sure if that ever happens actually—when fear no longer sets in. But this is what I tell myself when in doubt.