If the issue tomorrow is volume, try a little bit of teasing at the crown or roots and some hairspray. If you end up with kinks or bends, use a flat iron. If it's flat and you want more volume throughout, turn your head upside down and spray a light mist of flexible hold hairspray all over. Dry shampoo is your best friend also!
ETA: If you had the stylist put any kind of wave or slight curl at the ends (a la Duchess Catherine) pin your hair up overnight in a very loose bun on top of your head, DO NOT use a pony tail holder only bobby pins, and make sure the bends in your hair are going the right direction in the bun.
I've had long hair for a while, and usually blow dry it myself, and only wash it once or twice a week. I'm a pro at styling