Self-confidence is the first ...

Self-confidence is the first requisite to great undertakings.
Self-confidence is the first requisite to great undertakings.

More phrases

It really is all about believing in yourself: 80 per cent mental, 20 per cent physical.
 Victoria Pendleton
Courage - a perfect sensibility of the measure of danger, and a mental willingness to endure it.
 William Tecumseh Sherman
Regardless of how you feel inside, always try to look like a winner. Even if you are behind, a sustained look of control and confidence can give you a mental edge that results in victory.
 Diane Arbus
Courage is rightly esteemed the first of human qualities... because it is the quality which guarantees all others.
Optimism is the faith that leads to achievement. Nothing can be done without hope and confidence.

Quotes from the same author

If a man does not make new acquaintances as he advances through life, he will soon find himself left alone. A man, sir, should keep his friendship in a constant repair.
To keep your secret is wisdom; but to expect others to keep it is folly.
Love is the wisdom of the fool and the folly of the wise.
Memory is the mother of all wisdom.
Friendship, like love, is destroyed by long absence, though it may be increased by short intermissions.