Smoothing of hair is probably the highest priority task for all the portrait photographers. Your make-up artist might be great but I bet she cannot do her job as much perfect as Photoshop can do within minutes.
In fact, many times I have seen photographers asking same question: How do I smoothen hair in Photoshop? So I have decided to write a tutorial on smoothing of hair in Photoshop.
The very first thing we need to do is to duplicate the background layer two times. You can do it by either going to Layer>Duplicate Layer two times or by pressing Ctrl+J/Cmd+J twice. In case you want to remove the stray hairs too, you can refer to my Removing Stray Hairs tutorial.