Confidence and self-esteem are not the same.

Confidence and self-esteem are not the same. 

Self-esteem refers to general feelings about yourself; confidence refers to your belief and feel in that you can perform a task successfully. 

You may have have good self-esteem but no confidence that you sky dive out of a plane or return a serve by Federer. 

The better you feel about yourself, though, the easier it becomes to build confidence for a specific task

The evolutionary aspect to confidence
Looking at confidence through an “evolutionary-clinical lens.” After all, nobody invented confidence—it evolved because it gives you an evolutionary edge—to help you approach a task without trepidation.

you come across someone who appears super confident, it is envy making

So what type of experiences do you think he or she had to be who they are today. In other words, “How did they become so confident?'

Accurate Self-Assessment: Many parents tell their kids they are great in everything, that they are talented and beautiful. This can result in overconfidence and distorted self-perceptions that inevitably are exposed and in fact, devastate the individual when the truth be known. Many schools are relentless in praise and often blind the student to where he or she needs to improve. Not every kid is a great artist. Many take this approach because they think it will build confidence, but in fact it doesn't. Confidence, or self-efficacy, is built by experiencing achievement, not through hollow praise.

Confident people grew up with a realistic appraisal of their abilities and thus knew where they stood. This allowed them to develop a strategy and plan to strengthen themselves and to use improvements to creates a positive feedback loop that strengthened their perception they can influence outcome, a perception that reduces anxiety when you enter pressure moments.

Confident people engage Engage in Positive Visuals: If you can't imagine yourself being successful, confidence will be hard to come by. Confident people have a history of having playful positive visualizations of themselves in all sorts of moments. Throwing a touchdown, winning a beauty contest, discovering a cure for cancer, accepting academy award, running the country. The length of these mini day dreams is often a few seconds but having them "feels" confident.

Confident people look on Criticism as being a source of ProductivityMost people view criticism as a threat, a put-down, an attack. When you view criticism in this manner, it prevents you from benefiting from the information that you are receiving, information that often helps you improve and do your task better. Confident people, in grade school, high school, and college handled criticism differently. They perceived it as "information that can help them grow," and as a result, improved their task performance and boosted their confidence the next time they had to perform the task.

The majority of people have had a loving and Supportive Background: Confident people usuually gro w  up with strong support systems starting with parents who were encouraging and offered "unconditional love." The confident child felt secure and thus fear of failure became minimized and learning easier when approaching a new task. This allowed them to approach their pressure moments--trying out for a play, spelling b, current event presentation, with a positive attitude.