While the steps to spinning yarn are very easily broken down: stretch out the fibers, add twist, voila, yarn is born! Drafting is not as simple as that. Different fibers call for different drafting techniques. The desired yarn result is also a factor in deciding which drafting technique to use.
Some basics are common to all drafting techniques. The back hand provides a separation between the drafting triangle and the rest of the fiber supply. The front hand controls the progress of the twist from the flyer to the drafting zone. The space in between the front and back hands is the drafting zone. This is where the aligned fibers take up the desired amount of twist prior to being fed into the orifice and onto the bobbin. The front hand also feeds the completed yarn into the orifice to be wound onto the bobbin. The forward draft means that the front hand moves toward the wheel while the back hand remains stationary. The backward draft means the back hand draws the fiber away from the wheel to get the amount of fiber desired, and the front hand merely pinches the yarn to stop the twist when needed.
To spin a short fiber length, a short draft is usually best. Short drafting can be done either in a short forward or a short backward style. The short forward draft, also known as the inchworm method is the technique that is most often taught to new spinners. This draft is also used to create textured or slubby yarns. The front hand can push a bit more fiber into the yarn to create a thicker spot. This seems to come naturally to new spinners, while we more experienced ones have to struggle to overcome our habit of creating even yarn.
Spinning a long staple length lends itself well to a long draw. This also allows the spinner to get a good look at the yarn result before it is wound onto the bobbin. Because of this, the long draft technique should be taught more often to new spinners. It can be adapted to short staple lengths by holding a large fiber supply in your back hand. This allows you to let the fiber feed out more quickly, as would be needed for a short fiber.
The most interesting drafting technique is spinning from the fold. To spin from the fold, use a long staple fiber, alpaca works really well for this. Place a flick carded tuft over your index finger. Clasp the ends in a pinch of your thumb and the side of your middle finger. I prefer to do this on what would be my back hand if I were using another drafting method. Allow the fiber to feed off of the tip of your index finger. This is not a technique that I often use, so I do have to have my front hand at the ready to pinch in case too much twist is entering the drafting zone. Some spinners who use this method often are able to keep their fiber supply hand still as they are spinning. I find that I must still draw backward to achieve an even yarn.
Remember, there are no spinning police to tell you that you are doing it wrong, so spin the way you feel most comfortable, and gives you the yarn you want.