S.U.R.V.I.V.A.L., The US Army Way
Survival tactics haven't changed all that much over the years. And rightly so since the underlying premise of wilderness survival is to make do with the basic resources that nature provides. And so it shouldn't be too surprising that an acronym developed by the US Army decades ago is still relevant today even when we disregard the combat-related overtones present in its creation.
Size up the situation
Undue haste makes waster
Remember where you are
Vanquish fear and panic
Act like the natives
Learn basic skills
Size Up the Situation
Quite simple, when you're in a survival situation, take stock of your situation and be realistic with your assessment. Although you may hope to be rescued within hours, it is more prudent to assume that you will be on your own for days. Also assess your environment and determine what your priorities will be as they will certainly differ depending on things like how cold it is, how dry it is, and how plentiful resources are.
Undue Haste Makes Waste
Your gut reaction may be to find a "way out" of your situation by moving quickly through a forest or over mountains. This sort of carelessness can lead to serious danger as you expend your energy in what is likely a futile effort. Instead, think about the steps necessary to ensure your survival and your safety then move through them methodically.
Remember Where You Are
This item refers to blending in to avoid being identified by the enemy. This goes back to the combat overtones I mentioned and of course is not really relevant to typical wilderness survival situations that most of us need to worry about.
Vanquish Fear and Panic
Fear is normal and it is quite likely you will feel some once it becomes apparent that you need to take your survival in to your own hands. The key is to not let the fear turn in to panic especially when you are injured since panic will surely cause you to make mistakes further endangering your life. By acknowledging your fear and coming up with a plan to address all of things you fear, you will automatically become calmer.
Wilderness survival is all about taking advantage of the resources at hand to improve your situation. A little creativity and willingness to try new things will significantly increase your chances of still being alive when rescue does arrive.
Hope is key to wilderness survival. It will keep you moving forward with activities such as a building a shelter and securing food and water. Things like being hungry, cold, and wet can affect your ability to keep a positive outlook so be sure to address these basics.
Act Like the Natives
This is another item related to combat situations where you are in enemy territory. If you act like those around you, will not be easily identified as an outsider. Of course, when lost in a forest or desert, this is of no concern.
Learn Basic Skills
It's better to know how to survive in the wilderness long before you ever need to use such skills. That's what this site and numerous books hope to achieve.
FM 21-76 Survival, Department of the Army Field Manual