Without knowing exactly what you are doing it's hard to tell. But you can put the plates in the oven and preheat them, they will stay hot for a good 15 minutes.
You can also pre-plate some things. If you are doing a composed salad, you can have some items on the plate way before. All you need to do is dress the lettuce.
Same with crudo, ceviche, tartare.
Sauces in squeeze bottles, not ladled.
Same with gastriques.
Keep your proteins warm in a...