First, ask yourself "Can I clearly articulate and convey my belief, both to myself and to others?"
Continue to the next step only after you can answer the above with definite "Yes".
Next, ask yourself: "What evidence would make me change my mind about this belief?"
If the answer is "practically none" then you have discovered a crony belief.
If the evidence shows up and as a result you just move the goalposts to keep the original belief, then you are still infected...
We all need to model reality to survive. The problems begin when we worship the model instead of the reality it is meant to approximate. Any belief is a model that we are invested in and can have various levels of "staying power". A Zen (or other spiritual practitioner) would tell you that strongest of those and the one we usually are most invested in is the belief of a believer...
The best antidote to crony or otherwise any false beliefs is deciding the benefit of uncovering of what is True is more important than any other benefit.
All the above of course is a belief as well, which I will gladly change given a good counter argument/evidence :)