If you are camping, or are lost in the woods, the most important thing to your survival is warmth. I don't know if you have ever done wilderness survival training with out a sleeping bag or tent, but let me tell you, without a fire mine was cold. I wasn't allowed to make a fire, but if I ever need to I can, and you need to be able to make one also or you could die.
Disclaimer: I will never say that fire is a bad thing. It saves lives both from cold and boredom when camping, but if left unattended or used inappropriately, it can be dangerous and unpredictable. Don't be stupid.
Step 1: Tools
You always need the right tools, whether your camping, going on a hike, or just away from safety. If you are in any of these places with out at least some of the following, only you can be blamed for your death.
A knife, good sized and strong
Flint and steel(Sorry, no picture),
9v battery and steel wool,
The matches should include both strike anywhere and light when wet, you could need either.
I suggest you have all of these, they are light weight and can fit in your pocket.
Step 2: Gather wood
This is very important, the wrong type of wood could cause your fire to go out, and if your in the woods without a car or you're lost, it could mean death. Don't listen to what anyone says, size matters. You want a few big logs, 2 or 3, but not to many. It takes a long time to get big logs going, and a lot of fire. But don't get only small sticks. They will light, but not for long. You want a big log (>3 in. thick) per 5 medium sticks (1-2 in. thick) and about 20 or more small sticks (Step 3: Gather kindling
Kindling is important. It's the little stuff that burns fast and hot to get the bigger sticks going. Pine needles are good, and you'll want a lot of them, but you also need another type that you make yourself. Look in the area around you to find a stick or piece of wood that has a lot of sap, it should be somewhat yellow, it doesn't matter if it's wet, the wider and flatter the better. Take a knife, you should always have one when allowed, and put it at a 85-90 degree angle to the wood. Push down to make nice thin ribbons of wood, it's kind of hard to do and if all you get its scrapings that's ok. Make a good size pile of those and keep it safe, it could blow away.
Watch out, you can light this stuff with just a spark and lose it all or burn yourself, seriously, be careful.
Also, if you know that you are going into the woods, keep some of these shavings in a bag in your pack, you can make them at home with a wood planer easy enough.
Step 4: Set up
Make a circle free from flammable materials, the last thing you want is a forest fire. If possible make a circle of stones to surround your fire.
Gather your wood and push the kindling into a pile with air in it (not compressed). Take the smallest sticks and make a cone around the kindling. Then take 3 large sticks and make a cone out of them surrounding the other cone. Pile the medium sticks against the large cone to make a wooden tepee.
Then use your match, flint and steel, or 9v battery and steel wool to light the shavings. They should get very hot and light the pine needles. This should light the small sticks and get a fire going. Add small sticks to it until the medium and large sticks get burning. Beware of to many pine needles, after they burns they turn to ash and could suffocate your fire.
The point of the cone of wood is to condense the heat and allow the fire to get going. If you have any paper or tp, add it in to help add heat, but don't block air flow to the fire.
Step 5: Keep it up
Keep adding sticks as the fire burns and don't worry if you tepee breaks down into a pile. It makes it easier to add logs to the fire. use a medium stick to push the wood around and get charcoal off the logs.