Pointing out others’ mistakes rarely encourages them to change their behavior, and it certainly doesn’t help them learn anything. People aren’t driven by reason, but by emotion; so a public critique is far likelier to reflect poorly on you than it is to make them change their ways.

Abraham Lincoln was nearly forced into a duel for criticizing an opponent. His new policy became one of understanding what drove his opponents, accepting their shortcomings and going easy on the open criticism, eventually even turning some into friends. 

Nelson Mandela was lauded as a courageous leader -- even when he was truly terrified. Like the time he astonished his bodyguard by calmly reading a newspaper while the plane he was flying on had engine failure.

Mandela himself, however, later confessed in private that he’d been truly terrified but refused to show it. Mandela knew that courage is a choice, and everyone can be courageous by learning to cope with your anxieties and fears every day. 

Niccolò Machiavelli held that using advisors well begins with knowing one’s own weaknesses and selecting advisors to offset them. It’s also necessary to know how to solicit advice the right way.

For Machiavelli, that meant showing advisors he valued their honest opinion and would not punish them for giving it. But, at the end of the day, he was the one calling the shots.

A leader needs to adapt to the situation. Study your environment and your competition to make the best of every opportunity.

Sun Tzu, counseled that a martial leader should observe the terrain to take advantage of its natural layout and stay alert for startled birds or beasts that might indicate an ambush. He also advised becoming a student of one's enemies, to know their signs of fatigue or desperation. 

A former slave inspired by the ideals of the French Revolution, Touissaint L’Ouverture defeated the European empires to found Haiti and expunged slavery from his colony.

Early in the revolution, L’Ouverture determined that he would never compromise on his ideal of complete abolition of slavery in the colony. L’Ouverture succeeded by getting clear on his cause and doing whatever was necessary to serve it, even if it meant fighting alongside European powers.