Ask people why they have been successful. Their answers will be filled with personal pronouns: I, me, and the sometimes too occasional we.
Ask them why they failed. Most will revert to childhood and instinctively distance themselves, like the kid who says, "My toy got broken..." instead of, "I broke my toy."
They'll say the economy tanked. They'll say the market wasn't ready. They'll say their suppliers couldn't keep up.
They'll say it was someone or something else.
And by distancing themselves, they don't learn from their failures.
Occasionally something completely outside your control will cause you to fail. Most of the time, though, it's you. And that's okay. Every successful person has failed. Numerous times.
Most of them have failed a lot more often than you. That's why they're successful now.
Embrace every failure: Own it, learn from it, and take full responsibility for making sure that next time, things will turn out differently.