Greatness is consistency over a long period of time.
In Grit: The Power of Passion and Perseverance, Angela Duckworth describes success as:
Talent * Effort = Skill ==========> Skill * Effort = Success/Greatness
If you notice EFFORT counts twice as you are trying to reach the pinnacle of success. Through Effort (practice and repetition) you will get better and the reward will get greater.