The leadership of GENERAL GEORGE WASHINGTON was a key to the American patriots' success.
Here are some additional factors that helped the patriots gain victory over the British:
They were highly motivated, fighting for their independence as a nation. They also knew that if they lost, the penalties for treason against the British were worse than death in battle.
They were fighting for their home turf on their home turf. They had "home field advantage," in a sense, knowing the geography better than their British adversaries.
The American side used whatever tactics were needed to win, rather than being stuck in traditional battle patterns that had been the norm for European warfare in the 18th century.
The American side also received a HUGE advantage of financial support and military support from France as an ally, which strengthened their side against the British. General Lafayette was one of the key French leaders who assisted the American war effort.