Flint and Steel
If you have been paying attention to any survivalist since the dawn of the 20th century, then you always carry a flint and steel set when camping. Combine that with your char, and you'll have a fire in no time.
The first step is to take a a hold of the flint between your thumb and forefinger, with plenty of room to strike it without self-injury. Grasp the char between your thumb and the flint.
Next, strike the flint with the back of the steel striker several times and sparks should fly and land on your char, which will begin to glow. Once your char is smoldering you can fold it up into your tinder nest and blow on it to start a full flame.
If you do not have a flint and steel set handy, then you can substitute quartzite and the back or your trusty pocket knife's blade.
You're in luck if you wear eyeglasses, because this method takes the least physical effort of any fire-making method out there. The first ingredient, and the most difficult to obtain, is a sunny day. Second, you need a pair of glasses, a magnifying glass or a set of binoculars. Oddly enough a clear balloon full of water or a piece of clear ice can also do the trick.
Angle the lens towards the sun to focus the beam into as small an area as possible. If you add water to the lens you will be able to intensify the beam. Put your tinder nest under this spot and you'll quickly have a fire.
Steel Wool and Batteries
The most party-trick worth of all these methods calls for just two things: steel wool and a nine-volt battery. There isn't much reason for a camper to have these ingredients and no matches, or no flint and steel set, but if you're just out to impress your friends with your fire-making abilities, then this is what to do:
Stretch your steel wool out so that it is approximately 6 inches by 1 inch. Rub the contacts of your battery on the steel wool until it starts to glow. Gently blow on it to encourage the flames, then introduce it to your tinder nest. The wool's flames are fleeting, so act quickly.