Fire
It is extremely important that you have a way to start a fire. The heat can keep you alive, allows you to cook food and dry wet clothing. The psychological impact of not having light can be devastating, even causing panic. Have more than one way to start a fire.
A disposable butane lighter is a quick, easy tool for making fire. It has to be kept dry and your hands have to be dry when using it.
Fire starter matches are a good back up to the lighter. These have a match head and body made of flammable material that will burn until your kindling catches fire.
A magnesium fire starter should be in every survival kit. To use it, scrape off some magnesium shavings onto a bit of tender and strike the flint body with a piece of steel, like your knife blade. The magnesium burns hot enough to dry tender that is wet.
Soak some cotton balls in petroleum jelly and store in a plastic bag. This will give you a ready supply of tender that will burn for a long time.
Shelter
Shelter in survival starts with your clothing. Cotton kills. Whenever you head out into the woods, wear appropriate clothing, avoiding cotton. It loses its insulating properties when wet, even from sweat. Also, it takes a long time to dry. Wear polyester or nylon. Socks should be wool.Dress in layers and carry extra clothing with you.
In your survival kit have a mylar blanket. You can wrap yourself in it to keep warm, fashion a lean two with it and use is to signal for help. The reflective surface is large and can be seen from great distances.
Signaling Devices
Your survival kit should have both audible and visual signal devices. A survival whistle made of plastic that does not have a bead in it works well. The sound carries far and gets people's attention. The universal signal for help is three sharp bursts of the whistle.
You also need a visual signal. Old CDs are wonderful. They can be seen from as far as 5 miles away, and the hole in the center can be used to aim the reflected light. To use, hold it up to eye level and aim it at the face of would-be rescuers. You want them to see the signal. Flashing a light across the face will get someone's attention.
Water
Water is needed to stay alive. Your survival kit should have more than one way to get drinkable water. There are water purification bottles that are compact, easy to carry and use. You should also include water purification tablets as a back up to the water bottle.
Filter any water through a bandanna or piece of clothing before purifying it.
Food
Add some nonperishable food items like energy bars or vacuum-sealed foil packets of tuna or salmon. These will stay good for about a year and provide you with a needed meal.
Rope
A light rope can prove invaluable. You can use it to help in making a shelter, to tie splints and to aid in descending a steep hillside. Parachute cord is a good inclusion in your survival kit. It is lightweight and strong.