First of all, you need to address the issue of food and water.  Know how much of it you will need to survive for about 3 days and pack as much of that as you can.  The next couple of items you should consider would be fire and shelter.  Fire is extremely important and I recommend you pack at least two different methods of creating it.  One is the obvious butane lighter, but you should also pack a low-tech way of creating fire as well.  Shelter can be anything from a poncho that you can tie off as a makeshift shelter, or a tent that you tie to your bug out bag.  You should also consider first aid and rescue.  You never know what the disaster that you are bugging out from may bring in the way of injuries.  Pack a good first aid kit and know how to use it.  By rescue, I mean making yourself known to rescuers so that they can see you and get to you to rescue you.’