More than anything you have to believe in yourself.
You have to have the belief and attitude you will do whatever it takes to make it happen. The obstacles do not matter because you have made the decision that whatever resistance happens you will overcome it. You have the perseverance, confidence and intelligence to solve any problem.
Even when you do something stupid and it is your fault you do not beat yourself up. You know you will learn from the mistake and do better next time. You have complete belief in yourself.