Mnemonic devices are useful for preventing finger-in-the-air proclamations at cocktail parties that are dead wrong. One classic example is differentiating word origins and the insect kingdom with clarity between etymology and entomology. You don’t want to be schmoozing it up at a garden party with Thurston Howell the Fifth—millions at stake—and blather on about the Japanese entomology of “tycoon.” Your sycophancy will have been all for naught. The easy solution for avoiding the etymology/entomology trap is to associate "entomology" with ants.
The mnemonic I like for remembering that “mnemonic” begins with a silent “M” is by associating the word with that modern master of morphology, Eminem. Do you have any favorite mnemonics?