From the First Round blog:
Hiring amazing talent is both the most difficult thing a founder will ever do and the most transformative for their business. “If you’re not spending at least 50% of your time hiring — and that’s the minimum — you’re already on the road to failure,” says Hayes. Despite this fact, he’s seen dozens of entrepreneurs avoid this responsibility. And it always comes back to bite them.
Good advice (though not all would agree). There’s a lot more in the post: trust the people you hire, hire before you need to, and a few more very salient tips.