"What can a person w/ nowhere near EMT skill level do while waiting on real EMT's?"
You can make sure the victims have the basic Airway, Breathing, Circulation. If someone is bleeding, apply direct pressure. If the victim seems "shocky", keep them warm, raise the feet if possible. If the victim has broken bones, keep them still and splint the limb if feasible. If the victim is agitated, try to get them to sit quietly. Before the accident, it will help to have taken an ARC First Aid class.