Hair can be such a fun process especially when you use interesting brushes. Creating your own brushes can afford wonderful textures and effects.
I start out with a custom brush that I use to create the base of the hair. This custom brush is made by opening a new document and creating a new layer, which I paint dots to using a hard round brush.
After I am satisfied with the look and placement of my dots I lasso these marks, activating Edit>Define Brush Preset. Now I have my new brush saved and I will then edit this further using Brush Preset options.
I then set Shape Dynamics Size Jitter at 0, Control set to Pen Pressure, Diameter to 0. This will help your brush ends taper nicely. If I want to create even more texture with my new brush, I will apply Dual Brushing, Transfer and Shape Dynamics. I find these offer beautiful effects for hair.
Set Size, Spacing, Scatter and Count as you prefer. Finally activate Transfer and set Opacity Jitter Control to Pen pressure allowing the ends of your brushes to fade.