What factors led to george washingtons victory against the british

First, the skills of George Washington. Even in front of enemies, he had all the courage needed to encourage troops to fight, in addition to his good tactics against the enemies.
Secondly, The big distance between the colonies and GB. British troops had to travel the whole Atlantic ocean (It used to take a VERY long time back then), so it took time to supply the army and get reinforcements in time.
Thirdly, The French assistance. Their naval fleet helped the Americans to outnumber and overpower the British troops, which led to the American Victory in 1781.

Hope this Helps! :)