If you're allowed to go outside of the normal up dos then I recommend checking out waterlily716's youtube channel. But if all else fails I would do the bun or French Braid. Especially if it's really formal.
Low Poo-Organix Coconut Shampoo
Condtioner-Organix Coconut Conditioner
Products- LA Sports Gel, Organix Coconut or John Frieda serum, Hair Mouse when desired,