The postulates are that we are blind, fallible, and prone to "cargo-culting". So, in that setting, the preliminary step for any inquisitive mind should be to make space for the truth to emerge.
Hopefully, if you labor the intellectual land, ruthlessly digging deep, much deeper than you would normally do, then you might find important truths trapped beneath concepts and ideas which no one questions. As it turns out, it seem that important truth hide behind simple but devastating lies. More generally, Thiel calls these truths secrets, I much prefer the term treasures, or even things that were hidden since the foundation of the world if I'm in a biblical or Girardian mood.
In the context of technology and entrepreneurship, the postulate is that business leverage these secrets are the best kind. That is the whole argument that Thiel very eloquently lays out in his book From Zero To One.
But because critical inquiry is not something that comes naturally to most people, you need to train yourself and condition your brain to be effective at it. That is, control the mind's natural inclination to reject what goes against the doxa. The first step toward this is of course to be generous with odd ideas, and then grooming yourself to put your own beliefs in danger. It is an exercise in self-deconstruction and discipline. What belief makes you uncomfortable? Why? Keep pushing until your mind collapse under its own contradiction, until you have toppled every single of the foundations which hold up the larger edifice - if you are familiar with Cartesian doubt, that is exactly what I am talking about, only more violent.
When people discuss about contrarian thinking, they immediately think of controversial ideologies and political stances. In fact, I think these are some of the least interesting spaces to explore. I am much more excited about critical inquiries that lead to insights that people are, at first, indifferent to. They grow very deep and are most fruitful.