The Continental Army had strong military leadership including George Washington, Marquis de Lafayette, and Wilhelm von Steuben. These leaders made good decisions throughout the war to help the army defeat the British.
Shortage of Soldiers
The colonists were passionate about the war because they knew losing would make British punishments much worse than the punishments the British had originally enforced. The colonists had immense Patriotism as they gave their lives to ensure the safety of the other colonists.
Inferior American Training
Different countries, including France and sometimes Spain, supported the colonists in the Revolutionary War. France had a long-lasting hatred for England and France also lost its territory in the New World due to them. Thus, they provided around 90% of the gunpowder in the first two years of war.
Shortage of Supplies
The Continental Army was frequently short of skilled men that were ready to battle leaving it sometimes unstable. George Washington had only around 20,000 troops maximum at a time in many battles. Also, these men were mostly farmers and regularly traveled home and cared for their farmlands.
Many American soldiers were untrained, as many were just simple farmers and civilians. Many fought well behind cover, which is known as guerrilla warfare. Though, when face-to-face with the superior and prepared British army, most colonist soldiers would either fall or retreat.
The Continental Army was very short of supplies including gunpowder, guns, and uniforms. Food was also short which caused soldiers to leave the army entirely due to starvation. Also, the Articles of Confederation, which was the government during the Revolution, had no power to tax for supplies.