Suppose you have an original theory of how the world works.
Consider the following. Do physicists tend to find excuses to go visit their mothers-in-law when you show up? Do you find yourself banned from a lot of physics comment threads? Does your brilliance tend to go widely unrecognized? If you have considered the conventional explanations for this kind of shunning and they don't cut it, it's possible that you might be a crank.
My version of crankology depends on two simple tests. Have you learned the tools of the usual physics, as demonstrated by being able to work, say, the problems in Jackson's Classical Electrodynamics? Can you describe a quantitative test that reveals the difference between your theory and conventional physics?
If your theory of the world fails one or especially both of those criteria, you are probably a crank, and may I just suggest that you try another line of endeavor? Physics already has its share of such prosetelyzers. Perhaps you would be more comfortable in economics, where essentially all of the theorists would be more like you.
If the above don't give you quite enough guidance, more detailed versions can be found in John Baez's Crackpot Index or Gerard 't Hooft's guides HOW to BECOME a GOOD THEORETICAL PHYSICIST and HOW to BECOME a BAD THEORETICAL PHYSICIST. From the latter:
It is much easier to become a bad theoretical physicist than a good one. I know of many individual success stories.
PS - Even if you fail all of the above, you may be able to get an audience for your ideas if you provide donuts and coffee, or, better, beer and pizza.