Draw your own hair - part 1

When you start from scraps, it'll be nice to make a quick drawing to fit your hair.
The implantation of the hair will be on the red line, 45° from the ear to the forehead. Also draw the general shape of the hair

Use your Pen tool (P) to define the shape and fill it with a MIDTONE color. If you wich to do black hairs, don't put a pure black color, or you'll have problems for burning and dodging later.

Mine will be red hair, so I choose a tone not too light and not to dark.

Basics for hair is starting ugly and make them nice. For all the process, your best friend will be Smudge Tool (R). Blur tool is forbiden here.

Make a new layer.
Take a small paintbrush (3' here) with a color a little bit darker than your shape's color.
Make strokes following the shape of the head.

Notice that in real life, hair don't follow always the same direction from one lock from one to another. (See examples)

Do the same, this time with a lighter color.

Now smudge the stokes, always keeping in mind the direction of the locks.

Here, I selected the basic shape so my strokes don't go everywhere.

Now, I gonna focus on the highlights of the hair.
Take a small brush again and repeat step 3, where the highlights should be. You can do it on a new layer and with differents colors (always light)