Primary sources are the main place where historians find their evidence: they are the documents, artifacts and other material that was made at the time you are studying, or by people who had first-hand knowledge of the event. For this project, you will most likely want to find a primary source created at or near the time of the Revolution in the 1770s-1780s.
Founders Online
Search the correspondence and other writings of six major shapers of the United States: George Washington, Benjamin Franklin, John Adams (and family), Thomas Jefferson, Alexander Hamilton, and James Madison. Also includes letters from others (like Abigail Adams) who are part of the founders' archival collections. Over 181,000 searchable documents, fully annotated, from the authoritative Founding Fathers Papers projects.
America's Historical Newspapers
This database (requires a subscription, but FREE for Pacific students) includes dozens of American newspapers from 1784 and later.
TIPS:
The sources above provide many possibilities. But if you want to search for your own documents outside of these links, you can. You will have much greater luck if you pick a particular aspect of the Revolution to research. If you can't think of keywords or dates to start out with, scan through the Wikipedia Article on the Revolution to get ideas. For example, you might try searching for: