More one for Mums, really.
On Christmas eve, have 2 matching pillowcases/Santa sacks/stockings (delete where not appopriate). Let children place an empty one at the end of their bed, place the filled one in a place of your choosing (in our case, a locked section of our wardrobe!).
Instead of doing the "big switch" when you go up to bed, and risking them waking up at 2am to find "he's been!" and subsequently being overtired before lunch, set your clock for around 5.30, 6am, do the swith, then enjoy a cup of tea and exchange of presents with dh before the children wake up. (You can also put the prepared turkey in at this time if it suits your eating plan)
This has been known to go wrong when ex-dh got fed up with waiting and went into the boys room and woke them up saying, "Father Christmas has been, look!"
Of course, this all depends on your own family traditions, I know in some cases Father Christmas leaves presents under the tree, rather than at the end of the bed!