A few patterns worth recognizing before you go.
Common scams share a pattern: creating urgency, involving a stranger who's unusually helpful, or directing you somewhere off your planned route. Fake taxi meters, distraction theft, and overly persistent street vendors are worth watching for in busy tourist areas.
For road trips specifically, be cautious of strangers flagging you down about supposed car trouble, a tactic sometimes used to stage a robbery. When in doubt, drive on to a populated, well-lit area before stopping to check anything.