Delegate EVERYTHING. You will have to do the things you forget about (also, a runner is good for that).
Make sure you have a “coach” to run your team that night. It can be tough to try to run the meet and manage the team at the same time.
Reserve enough rooms: 14 is probably good. 5 homerooms, 4 contest rooms, 3 orals, 1 grading, and 1 hospitality. If there are very few alternates, you can always combine them that night.
Reserve your awards space as early as you can. I know our auditorium gets booked a lot.
Get helpers as soon as you can (check to see that your school can pay them and promise food) - 4 proctors for written, 2 for orals, and about 4 graders (one who can do data entry helps), and a runner - at least 11 besides you and your team coach
Lots can be done ahead of time. Have others order the food/snacks and candy bars. People want to help but cannot always help on the night of the meet. You are actually giving them the gift of service that way. Anything that can be done by someone else should be.
Have a competent non-coach make the photocopies. Often our department head would do that.
I put the written contests in envelopes with the scratch paper and proctor instructions. I write the room number, event, and start and stop times on the envelopes.
Many coaches use color paper to clearly identify the different contests and their corresponding blank answer sheets - this is a great idea. I use white for Candy Bar since we usually make the most of those, and it’s the cheapest.
Have the orals timer check the markers (chalk, whatever) in the oral presentation room.
We have had some of our National Honor Society students not on math team help guide teams around - they are often looking for ways to be of service to the school and get credit hours for NHS. Talk to their sponsor, or have a student bring the idea up with them.