Compass: One of the foundations of survival packs, the compass will point you where you need to go for help. However, you need to know how to read a compass. It is astounding how many humans cannot do this.
This is how my boss told me to park Fed Ex trucks. He's been fired for a while now.
Mirror: Any small piece of mirror will do when you are trying to signal rescue planes above, but we prefer the ones that look like cookies.