Answer:
The idea that the American colonists strictly used guerrilla tactics and acted as snipers from the forest, while hapless British soldiers lined up in the open and followed the rules of European warfare is part of the myth of the American Revolution, and is often dismissed by modern historians. However, it is based on reality to a certain extent. In fact, according to Anthony J. Joes, the guerillas' contribution was extremely important to American independence.
There were certainly instances of the Americans using guerrilla tactics, particularly following Lexington and Concord in Massachusetts and later in the South by such partisan leaders as Francis Marion. These guerrilla bands managed to wear down Cornwallis' force with hit-and-run tactics and the destruction of supplies, making his army more vulnerable when they finally confronted the main Continental Army at Yorktown. Furthermore, American riflemen, or rangers, when led by officers who knew how to utilize them correctly such as Daniel Morgan and Nathanael Greene, were extremely effective.