If you watch TED talks, I would recommend taking a look at Angela Duckworth's discussion on the formost predictor of success and I would guess it's not what you think. She studied Chicago public schoolchildren from a wide variety of social and ecnonomic situations.

"It wasn't talent or brains. It wasn't social intelligence. It wasn't good looks. It wasn't physical health. It wasn't IQ. It was grit" she said.

Duckworth defines grit as "a passion and preserverance for very long-term goals." She explained: "Grit is having stamina. It's living life as a marthon, not a sprint."

Do you have grit?