Believing you will succeed is key, but believing you will succeed easily (what I call “unrealistic optimism”) is a recipe for failure. Take it from the women, all obese, who enrolled in a weight-loss program in one study. Those who thought they could lose weight easily lost 24 pounds less than those who knew it would be hard. The successful dieters put in more effort, planned in advance how to deal with problems, and persisted when it became difficult. Don’t try to tamp down your worries — they can help prepare you for shape-up challenges.
And train hard. The same is true for your performance goals as well.