That may seem like an obvious statement; let me say it in a way that I think really sums it up for me:
You don't become successful by giving up
All the publications, TV and mentoring organisations hold up examples of successful businesses and the people behind them. They tell you to listen to their story, learn from what they've done and use their example as inspiration.
But I think that the single most important thing to understand is something these successful people have in common - they never gave up, they had absolute belief in what they did and that confidence helped drive them to their destination - success!
Short and simple:
Success = not giving up