Teach the trick you’re proudest of. If it still works once everyone knows it, it was real.

A method that only works while it is secret was never as strong as it felt. Keeping it hidden protects you from a test, because if the advantage vanishes the moment other people know, the advantage was scarcity rather than quality. Real craft survives being explained. It often improves, since other people refine it and hand it back to you better than it was.

So teach the thing you are proudest of to somebody who could use it. Watch what they do with it, including the parts they do differently. Then decide whether yours was really the best version.