While the Hale mission ended in disaster, Washington quickly learned the art of intelligence. With the help of Benjamin Tallmadge, Washington managed the Culper Ring, an organized spy ring operating around New York. Washington understood the value of intelligence--and secrecy. In letters to his spies and other Continental Army officers, he stressed the need to keep their operations secret. He had his spies also write in invisible ink, a creation of John Jay's brother, James.
Washington also proved a ruthless spymaster. He suggested that the Americans recruit Quakers, who were conscientious objectors to the war, as spies because the British would not suspect them. He also had a chaplain use the last rites of two condemned British spies as an opportunity to obtain intelligence from the men. Finally, he supported efforts to intercept and decode British diplomatic and personal correspondence, an activity that the later Secretary of State Henry Stimson called ungentlemanly.
Over the course of the war, Washington's intelligence activities continued to grow. The problem with Washington's model was that he was the center of operations. There was no formal organization with an effective management system to conduct intelligence operations and then analyze the intelligence collected. Another problem was that the Continental Congress did not exercise any real oversight or control over Washington's intelligence activities. Washington would later incorporate this same model as president: he would conduct intelligence operations as he saw fit with no oversight by Congress.
But Washington's intelligence activities in North America for the Continental Army were only half the intelligence war. The other half was happening across the Atlantic, in France. There, American "diplomats" like Ben Franklin were actually also acting as intelligence officers. However, their intelligence operations were plagued with mistakes of their own doing. They also demonstrated the problem of mixing intelligence and politics--a problem that continues across American intelligence history into the present day.
Source: https://commons.wikimedia.org/wiki/George_Washington#/media/File:George_Washington_by_Peale_1776.jpg