I would use a quick alpha channel mask.
Open your channels panel.
Select the best channel offering the best contrast.
For this image it was the red channel.
Right click the channel and choose 'duplicate channel'.
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Use level adjustments to increase the contrast.
The objective is to have a completely black and white channel.
Use your Brush Tool to fill in the center of the woman's face.
Use your Dodge and Burn Tools around the edges to make the loose hairs darker.
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Once you have your alpha channel ready, Cmd/Cntrl + Click the thumbnail to make a selection.
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Go back to your layers panel.
Add a layer mask to your image.
This should do a decent job of isolating the hair. You may need to use 'refine mask' > decontaminate colors to work out the yellow tinge.
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Here are some links to look at:
Channel Selection:
https://www.youtube.com/watch?v=TJR20e7JcBg
http://planetphotoshop.com/masking-with-channels-2.html
http://planetphotoshop.com/using-channels-to-make-better-selections-in-adobe-photoshop.html
http://phlearn.com/separate-parts-of-your-image-with-photoshop-channels
http://layersmagazine.com/planet-photoshop-masking-with-channels.html
http://planetphotoshop.com/masking-with-channels.html
http://www.youtube.com/watch?v=jvBAvZyqPmU
http://www.youtube.com/watch?v=GsXbDLglasA
http://www.youtube.com/watch?v=k-aizjdm5Us
Calculations:
http://www.youtube.com/watch?v=Vqg4m2q2eek
https://www.youtube.com/watch?v=33tz2Xszil0