Step 8 - Finishing UpMerge the two hair layers and blur or burn the part if you feel it is too distinct.

Go back to the base (head) layer and darken the areas of the forehead upon which a shadow would be cast from the hair.

You're done!

If you don't like the color you chose for your hair, simply go to Image>Adjustments>Hue/Saturation to change the color!
I felt that the hair color I chose was a bit too bright and unrealistic, so I went to Hue/Saturation and reduced the saturation a bit.