Always start by making the frosting 2-3 days before you need it, bake a day before and structure and assembly are usually on the day of delivery unless the event is early in the morning. And before all of that start preparing the parts of the design to have enough time to dry.
Most importantly don’t skip on sleeping or eating and remember to take breaks because your body needs them to be able to keep going…

So, plan ahead so you don’t give up what is essential for your body to get your work done.