The Key to Winning by Denis Waitley
(excerpted from Becoming an Authentic MVP)

People often ask me, what is the most critical attribute of a winner in life? Without hesitation, I answer that believing you deserve to win is the key. If you believe in your dreams when they’re all you have to hang onto, you begin to try. If you feel you have potential or talent, you’ll invest in it. If you believe you’re worth the effort, you’ll put in the time and energy. If you think you can, you’ll learn how.

Healthy self-esteem is perhaps the most important and basic quality of a winning human being.  You want to be able to say: “I like myself. Given my parents and my background, I’m glad I’m me. I realize I may not be the best-looking in the group, but I always look and do my best in every group. I’d rather be

Confidence - You Only Sell You by Denis Waitley

Here is very good article on confidence.
 
Confidence - You Only Sell You by Denis Waitley

In my opinion, there is nothing more important than your belief in your own potential for success and happiness, regardless of your age, gender, ethnicity, looks, education or background. The truth is, every day "You only sell you. You don’t sell products or a business concept. You sell the value of the person offering the products and services. The decision of the buyer is based on the value of the seller. Just as products are branded as "the best", "cheap", "ineffective", "trustworthy" or "unreliable", so, too, are individuals branded by others as "winners" or "also-rans."  Who you are shots so loudly, that people either can’t hear, don’t want to hear, or listen carefully to what you are saying. Everybody loves a winner, and we all want to buy from winners who pass their own value on to us.

Self-confidence isn’t something you were born with. It’s something you develop. Many of us were