Theme, games, menu and a timeline that survives the day — built around the guest of honour rather than around what showers are supposed to look like.
Whether she wants a shower at all, whether she'd enjoy a surprise, whether she'd rather die than play a game. It's the one question that changes everything and it usually gets skipped.
Measuring the bump with string, guessing her size. Plenty of guests of honour hate these and say so only afterwards, once it's too late to matter.
Soft cheeses, cured meats, runny eggs, the grazing board that's been out for four hours. The one guest the day is for often can't eat half of it.
It takes far longer than anyone plans for, and it's the stretch where the room quietly loses interest and she can't leave the chair.