How To Draw Hair (Long Hair)

One of the most common mistakes is to attempt to draw every hair as a pencil-stroke. A single pencil line cannot represent the many changes of tone along the shaft of hair, so this approach is invariably disastrous. Another problem is lack of care - you should spend at least as much time on the hair as on the face.
Drawing long hair is in many ways easier than short hair, as the 'surface' tends to be a little smoother, with broader sections of highlight, less dispersed than in short hair. Curly or frizzy hair can be more of a problem, but if you take your time and observe carefully, it is quite acheivable. You might need to ask your model to tame their hair a little with conditioner prior to sitting.

	First, look carefully at the model or reference photo and identify the major sections of hair. Curls will often be rather flat, like ribbons curling back on themselves. Try to ignore odd strands at first, concentrating on the main bulk of the hair, and lightly outline the main shapes and sections.
	Next draw in the darks with a soft pencil, being careful to leave the highlights well alone. At this point, you might wish to lightly sketch in prominent lighter hairs that need to be left, bringing the darks up close beside them, to avoid problems with erasing them. Where strands of hair cross, small marks may be necessary to separate them. Make sure you follow the direction of the curl.

Now that you've got the basic structure of the hair and put in the darks, you've won half the battle. Drawing lifelike hair is in part a test of observation, and in part a test of patience. This approach will certainly work for quick sketches when applied judiciously, but for really lifelike hair, you will need to take your time and pay attention to detail.

Now draw the mid-tones, with pencil-strokes following the direction of hair. Draw the darker lines separating sections of hair, and patiently draw the dark areas showing behind lighter hairs. At this point I use a harder pencil over the darks, filling in the paper-grain and blending the tone out along the hair. For super-smooth and shiny hair you can use a blending stump along the hair.

To finish off, I've added a few stray marks to loosen up the drawing around the edges. Some sections of hair are smoothed with a stump and highlights picked out with an eraser. The original drawing is a little sharper than shown by the scan - after blending tone and erasing, I use a hard pencil to lightly re-define nearby areas and keep them crisp. (Source by - http://drawsketch.about.com/library/weekly/aa032303b.html)