Also, look for guides and join the genealogy community. Ancestry, Family Search, and others have fabulous "how-to" guides for specific nationalities beyond the U.S. as well as just general tips. If you found people who have already researched your family history, be sure to check their sources.
You may find that you have to take a road trip to an archive, regional library, or local genealogy society. Don't just drop in and give them your family name, do some homework beforehand. The more information you have in hand, the better they can help you. Here's what you need have handy:
It's possible that the town or county has changed over time. Districts and counties in 1790 may be very different than today! Maybe a town didn't officially exist in the 1800s.
You can usually find this information online in places like Wikipedia. If not, you can find it in a gazetteer, which is a dictionary of place names. The library has gazetteers for North Carolina and the U.S. Most states have their own gazeteer.
Ancestry Library Edition focuses primarily on the United States, though new information is added regularly. If you hit a dead-end in Ancestry Library Edition, try these resources.
Consider subscribing to Ancestry.com, which has a few extra features than the library edition, including a World Explorer edition. A 14-day trial is available for free.