I like your mnemonics idea, though the part "Self-deprecation and Conceit" seems a little bit forced. Maybe make them rhyme or something else instead.

I think it's one of the most important things to teach someone about rationality (any other suggestions? Confirmation bias, placebo, pareidolia, and the odds of coincidences come to mind...)

The things that come to your mind are object-level skills. However I'd say that the most important thing to teach is the meta-skill of dissociation - looking at your thoughts as a machine with some properties, and controlling this machine from the "outside".

In other words, intuitively noticing that thinking something about X is not a fact about X, but a fact about your thoughts.

Having this habit that when you think X, you also automatically think "hmm, I seem to be thinking X, what do I make of it?".