The fish tape, or snake, is an important tool for everything from pulling wires through a pipe to fishing wires from one end of a house to the other above a ceiling in an attic or up several floors through a plumbing chase.
One of the first challenges the novice snake-user encounters is unrolling the snake. I'm actually planning on doing a separate instructable-tip for that process. But suffice it to say that you need to hold onto it VERY TIGHTLY and carefully walk out the entire length of the snake (stepping on it as you do so to keep it from sproinging out of control) and then re-coil it with a much larger diameter. Secure the larger coil by wrapping one end around the coil thru the center of it several times so that it locks against itself.
Step 1: Avoiding Major Trauma -- Keep the End Folded Over.
The end of the fish tape can be a very dangerous thing, so *never* leave a sharp end exposed -- if it ever sprung when you didn't expect it, it could leave a very nasty gash on you, someone else, pets, whatever.
Take the end of the snake in the grip of a pair of pliers and bend it over 180 degrees. Then crimp it down tightly, so that the sharp end is no longer exposed.
The loop on the end is also useful for hooking the snake at the far end when you are snaking in walls or ceilings and for providing a place to securely tie on wire or whatever you're snaking. Twist it through the loop and then cover the whole thing with electrical tape to keep it from snagging and to help keep it secure.
Step 2: Slight Bends in the End
When fishing through walls or ceilings, a slight bend or offset in the end of the snake can help the snake move forward without starting to coil in the void of the ceiling/wall. Also, flipping it back and forth through 180 or 360 degrees can help avoid having it coil up on itself.
You can have a great deal of control over how a snake slides against the wall or ceiling in a typical residential wall/ceiling void, but it's kind of an art. Experiment and see what works!
Step 3: Mark How Far You Think You're Going
Walk off or measure out how far you think you're going to have to extend the snake, and mark that by wrapping a piece of electrical tape around the snake. That will help determine if you're hitting an unexpected obstacle or if your snake has gone somewhere unexpected (a common occurrance when snaking through large voids like attic spaces).
Flipping the snake back and forth through 180 degrees or even 360 degrees will help ensure that the snake isn't coiling on itself. Remember to turn it both clockwise and counter clockwise, or else you might be putting a helical twist in it.