Just bring anything you would normally use in a three week period (except for makeup, ie. - at camp who needs blush, foundation, eye liners and all that stuff!!!). Off the top of my head, the following come to mind:
- toothbrush, spare brush "just in case", toothpaste, floss.
- shampoo, your favorite soap just in case you don't like the stuff the camp provides, moisturizer, lip balm.
- deoderant, foot powder.
- a few of those little packs of tissues: they come in handy sometimes!!
- tampons or liners
- a few basic personal first aid things: a few band-aids, small tin of aspirins, antibiotic ointment - a few little things which can be really useful when needed.