1. Extroverts can thrive in this business because clients are going to have questions about the places they're going to see. If your customer engagement skills are shaky, you may want to pass or hire someone who doesn't mind a lot of talking.
2. Find a theme that hasn't been covered. If a person lives in an area with several points of interest, they should find a way to market their services to local travel agencies, nearby restaurants, and other places that will benefit from cross-promotion.
3. Although tour operators generally aren't required to perform first aid, having a certification that's renewed regularly can certainly pay off. The same goes for CPR certification.
4. While some do a cash business, using an app like Stripe or PayPal reduces the risk of theft.
While not mandatory, joining a group like the U.S. Tour Operators Association can open up new opportunities. The advantages of this service are that it saves the tourist from having to drive around in unfamiliar territory, reduces airborne pollutants, and allows people to get acquainted in a fun environment.