• Admit to yourself the limits of your knowledge or intellect. Pretending, as a matter of pride, that you know enough to make a decision when you actually don't is a set-up for being gulled. We all have our limitations, and there's no reason to be embarrassed or ashamed about owning up to them--whether to ourselves or others. It's much better to admit that you don't have sufficient "gray matter" to fully comprehend what's being said than to fake such understanding--with the result that you end up capitulating to some manipulator who can talk circles around you and somehow convince you of something you never could grasp in the first place. Remember, not everyone is capable of understanding Einstein's Theory of Relativity, quantum mechanics, highly complex economic concepts, and the like. So, as Greenspan stresses in his Annals of Gullibility, it's essential to put off action or judgment in situations potentially misleading or dangerous.
• Get another opinion. Relating to the above, when you're uncertain about what to do--or what someone else is "on you" to do--don't be reluctant to consult another party (whether a friend, relative, associate, or professional). As long as you can be confident that the person you speak to has no "conflict of interest" in helping you make a decision, you're almost always better off when you don't "go it alone" in such circumstances.
• Avoid temptation. Oscar Wilde once claimed that "he could resist anything but temptation" (!). If, historically, you've demonstrated weak self-control in particular areas, it's important that you establish as many safeguards as possible to defend you from yourself. And the examples here are endless--e.g., resisting a scrumptious dessert that your waitress is promoting to fatten her tip; saying no to a salesperson who tells you that the outfit you've just tried on (though you can't really afford it) looks so sensational on you that it would be a sin to return it to the rack; or maybe a general inability not to comply with someone who just seems "so nice."
Protecting yourself in such circumstances might involve taking a friend with you to wherever you suspect temptation might be lurking--or staying away from the alluring or enticing situation altogether. The powerful expression (or warning) heard in 12-Step programs is unquestionably applicable here: namely, "Don't go into the lion's den unless you're a lion tamer."
• Become more self-sufficient and "self-liking." Neediness of any kind fuels vulnerability. If you have a strong need for others' support and validation, you'll be that much more susceptible to their taking advantage of you. So if you recognize yourself as excessively dependent on external validation, ask yourself whether it's time to learn how to become more autonomous and independent.
Further, if it's supremely important that others like you, you may place far too much emphasis on pleasing them--which, in turn, might make you especially susceptible to being gulled or cheated. It's crucial that we like ourselves enough not to "give away the store" to ensure that others will favor us, too. Keep in mind that unless you're liked for who you are, the other person's positive regard ultimately will do you little good anyway. You don't want to compromise your integrity merely to win someone else's approval. Whatever positive regard such self-sacrifice might "earn" you is hardly worth what you're giving away in return. Peer pressure and social pressure generally will have much less impact on you when you're no longer dependent on others' acceptance.
Once again, I'd advise any readers who have a seriously negative self-image to consider the possibility of counseling. (At the least, it might be helpful to read a much earlier post of mine called "The Path to Unconditional Self-Acceptance.") For as long as feeling good about yourself depends on others' liking you, you're all the more subject to being deceived or duped.
• Become more sensitive to non-verbal cues that you may be dealing with a fraud or "hustler." Any facial expression, body posture, or voice tone that doesn't feel right to you probably isn't. Don't just listen to the other person's language--observe their body language as well. Is there anything "shifty" about their stance? Do they avoid eye contact when they're voicing something that seems to you like an exaggeration (though, it should be added, a true "operator" can look you straight in the eye and say--with utmost conviction--the most incredible, far-fetched things you might imagine)? Is there anything about their self-presentation that seems suspiciously ingratiating? Do they convey a tone of flattery--which, if you still harbor substantial self-doubts, could make you especially vulnerable? Even if you can't quite put your finger on it, if there's something about them that makes you uncomfortable, you're better off trusting your intuition than putting your trust in them.
• Become more adept at reading others generally. Speak to friends and relatives about their own experiences getting "sucked in" or swindled--and what knowledge they acquired from the experience(s). Since everyone out there has been hoodwinked at some point, take the opportunity to learn from their mistakes. Additionally, review your own experiences of being gulled, and try to "tease out" the cues you may have overlooked at the time. Begin to appreciate that people who prey on others' confidence can have a certain magnetic charm to them (regardless of how superficial their agreeableness or allure may be). Even though you don't want to cultivate an embittered cynicism--and certainly not paranoia--it's only sensible to be cautious of another till you've obtained sufficient evidence that their motive isn't primarily to exploit you.
If, after consulting both with others and your own past experience, you still feel inadequately prepared to defend against those who might take advantage of you, it might be valuable to pore over Greenspan's Annals of Gullibility. For this book discusses a broad variety of ploys, schemes, and stratagems that have been successfully employed throughout history to fleece the unwary. So studying it might help you develop the skepticism that can protect you from putting your faith in some person or venture that really doesn't justify it.
• Get advice from people you trust. I've already made this suggestion in conjunction with earlier recommendations. But it's still worth singling out as a reminder that if you can't eliminate nagging doubts about something you're considering, it's best not to go ahead till you've run it by a person whom you know you can trust--whether that be a friend, associate, relative, or professional. And in such cases, don't worry about exposing your ignorance or insensitivity. If the other person would de-value you for such candor, he or she probably needs to be struck from your list of "advisors" anyway. The important thing is that you use all resources available to make the most informed decision possible.
This three-part list is hardly exhaustive. After all, the whole subject of gullibility resistance is surely worth a book unto itself. But I think that if you've ever struggled with gullibility, these many suggestions should enable you to cultivate a healthy skepticism--which in turn should "arm" you against those who view you only as an object for personal gain.
Finally, I invite all interested readers to follow my psychological musings on Twitter.