Before saying anything, I remember my obligations and ask myself, "will anyone seeing/hearing this know anything of the secrets of the Fraternity for having seen/heard it that they didn't know before?"
example:
your question alludes to Masonry, but it does not reveal anything. As to what not to say, I cannot give an example for obvious reasons, but suffice it to say that if one remembers and honors his obligations, then he will not do wrong.