Hairdos are the first order of business after all the ballerinas have arrived. Everyone needs a tiara, of course, and then you can go all-out with the rest of the hair accessories -- ribbons, barrettes, flowers, rhinestones, glitter spray, you name it. You could keep it simple, of course, but why? Remember that not every girl's hair will be long enough to put up into the classic ballerina's bun, but a few sparkly barrettes or bobby pins can go a long way in short hair.
It would be a good idea to have at least one extra parent, grandparent or friend on hand to help with the hairstyling duties -- you don't want the girls to wait too long before the main event ...