The most important tool you will ever have in a wilderness survival situation is your mind. If you do not remain calm and collected, you can make a poor decision that will make survival even harder. Even the most skilled survival experts can quickly make a bad situation worse by losing their cool. If you realize that you are in a survival situation, take a deep breath, sit down, and analyze where you are and how you got there. Do not try to back track, but rather take inventory of what you have and what you can do next.
A light survival guide can be found at any outdoor store and should be part of your survival kit. It can be helpful to have diagrams of how to find water, how to build a shelter or how to make an animal snare. Read your survival guide at least once and research other survival information before you need it. Instinctual knowledge that you have learned by studying is invaluable, especially in an emergency situation.
The human body can only go without water for approximately 72 hours, and during the last 24 hours you will be pretty much useless. Water must be your highest priority in a survival situation. Immediately ration what you have, drinking enough not to feel thirsty, but not guzzling it, and try to find a local water supply. Streams, lakes and rivers are excellent sources of water, but it must be treated before drinking. Include drops or tablets that dissolve in water, rendering it free of pathogens and bacteria, in your survival kit. These are available at any outdoor supply store. You can also sterilize water by boiling or filtering it.
Once you have secured water, your next priority is shelter. Even in temperate areas, a shelter can be helpful at night for keeping in heat, keeping out precipitation and for blocking the sun. In cases of extreme temperature, such as the desert or in heavy winter, a shelter will get you through the night. After dehydration, exposure to the elements is a huge danger in the wilderness. The most basic shelter can be made by creating a lean-to of branches against a sturdy surface, such as a fallen tree or a rock face. Include a tarp or a tube tent in your survival kit so that you can produce immediate shelter when necessary.
Food may seem important, but in terms of basic survival, it is far less important than water and shelter. You will be uncomfortable and weak, but humans can survive in the wilderness without food for quite some time. Include fishing line, hooks and lures in your survival kit. The fishing line can be used for fishing and for building small animal snares. Beef jerky, trail mix and energy bars are smart, calorie-packed snacks to have in your survival kit. Include herbal teas and bullion cubes, which can give you a boost if you have no food. Do not include caffeinated tea or coffee.