The most important event of my life thus far is happening tomorrow; could you please give me styling advice?

I would suggest your hair up, with a few small tendrils falling down. Soft makeup, lip gloss is OK, or a neutral lip color close to the natural color of your lips. I would suggest a hint of baby pink eyeshadow, as the baby pink will defuse flaws, if any, and make your eye looked revived. And just some mascara. You know what they say, less is more. Good Luck, and relax, I'm sure it will be great.