A speech of uniformly long sentences sounds like a lease; a speech of uniformly short ones sounds like a slogan. Compose this six-beat passage by choosing a long, medium or short version of every sentence, then read the breath meter and the diagnosis. Then switch tabs and build a line the ear can finish for you.
Six beats — pick one version of each
Why this works: the ear detects a pattern after the second item and starts predicting the third. Match the grammatical form and the prediction pays off. Break it and the listener stumbles — even if she could not tell you why.