OK Now that your starting on the right foot...
Lets get down to basics.
Bring a kit even if you have a makup artist. get a pro kit from Mac, or Bobbie Brown. Dont use your street makeup. Use your modeling kit only for modeling. Kit should include: several shades of lip gloss, powder, foundation, eyeliner, mascara, lipliner, and lipstick.
You should have a hair kit with scrunchies, ties, bobbie pins, straight pins, clips, extensions and anything else you can think of. Even a piece of rope or old Christmas ribbons can come in handy.
3. Stylist Kit :
Create a stylist kit from an old bag. Include rubber bands, tape, glue, thread, scissors, ribbons, magic markers, sunglasses, jewelry etc. Having a kit like this makes you prepared for anything.