One of the more useful lessons I’ve learned is to seek out and emulate role models. One such role model is Ray Dalio, the self-made billionaire investor and hedge-fund manager, who governs his life and work by hundreds of “Principles” or rules, which are documented in The New York Times bestseller of the same name.

Here are three principles that stand out.

"If you can't successfully do something, don't think you can tell others how it should be done."

Several years ago, a new travel agent coach contacted me. As I wasn’t familiar with her, I questioned her motives. She finally admitted to selling travel for less than six months, having decided she could earn more advising agents than being one. She wanted to offer my Wealthy Travel Agent programs to give her credibility and a de facto endorsement. I declined.

Lesson: Do your due diligence and trust your gut.

"Be especially wary of those who comment from the stands without having played on the field."

As a cruise line executive, I often found myself at odds with my peers, being the only person who had worked as a travel agent and understood agents’ real needs. Sales, marketing and training programs are typically dictated by corporate vice presidents who have never had skin in the game or sold anything—much less their own product. Yet because many agents, especially new ones, are wowed by fancy titles, they treat every word like the gospel.

Lesson: Question the credibility of those who have never played the game.

"Rember that believable opinions are most likely to come from 1) people who have successfully accomplished the thing in question at least three times and 2) who have great explanations of the cause-effect relationships that lead them to their conclusion."

When interviewing a supplier, consortium, coach or peer for advice or a partnership, ask probing questions and don’t be satisfied with the first response. Ask “why” questions until you are satisfied that the person or group is believable and has a proven system that can help you advance your own agenda.

Lesson: Make sure you cover all your bases in terms of the questions you ask.

Role models can play a key role in your success, so choose wisely—and beware of false prophets. A fancy website with pretty pictures and positive rhetoric can easily create a false facade of success.

Dan Chappelle is a sales performance coach, professional business advisor and bestselling author. His training and consulting firm helps develop sales-focused business leaders and entrepreneurs in the travel and tourism industry.