Teaching Email / The Message That Gets Read
Put the action in the first line, not the last.
Readers stop early, so anything that must be done should arrive before they do.
There is a natural instinct to build up to the point. You explain the context, then the reasoning, then what happened, and finally what you would like the reader to do. That order is how you thought about it, and it feels courteous, because arriving at a request immediately can feel abrupt. But the reader is not reading in order. They are reading the first two lines properly, skimming the middle, and leaving. If the request is at the bottom, a real fraction of your readers will never encounter it, and you will spend more effort chasing them than you saved by being polite.
Invert it. The first line says what is needed and by when. The rest explains why, gives the background and offers help. Nothing is lost, because the reader who wants context reads on and finds it exactly where they expect. The reader who does not need context has already got what they came for and can act. Courtesy has not disappeared; it has moved from the shape of the message into its wording.
This applies with more force to messages that carry a deadline or a cost. If a family needs to pay something, agree to something or return something, that fact should be visible without scrolling. Burying it and then treating non-response as non-compliance is unfair, and it generates a second round of correspondence that you then have to write. The bluntest test is to read only your first two lines and ask whether someone acting on that alone would do the right thing.