In promulgating your esoteric cogitations, or articulating your superficial sentimentalities and amicable, philosophical or psychological observations, beware of platitudinous ponderosity. Let your conversational communications possess a clarified conciseness, a compact comprehensibility, coalescent consistency, and a concatenated cogency. Eschew all conglomerations of flatulent garrulity, jejune babblement and asinine affectations.
Let your extemporaneous descantings and unpremeditated expatiations have intelligibility and veracious vivacity, without rhodomontade or thrasonical bombast. Sedulously avoid all polysyllabic profundity, pompous prolixity, psittaceous vacuity, ventriloquial verbosity, and vaniloquent vapidity. Shun double-entendres, prurient jocosity, and pestiferous profanity, obscurant or apparent.
In other words, talk plainly, briefly, naturally, sensibly, truthfully, purely. Keep from slang; don't put on airs; say what you mean; mean what you say.
And DON'T USE BIG WORDS!