It all depends what exactly you want to cut out and how complex that certain image is. Considering it's flowing hair, it doesn't really matter that much if you make a mistake, as you can touch up errors and create flowing hair yourself with the healing brush, smudge and blur filters.
If you're new to such techniques pick up some books on image manipulation. They should cover a lot of different cutting out techs used for various types of image. One book I recommend for both novice and pro alike is this...
Amazon.co.uk: How to Cheat in Photoshop: The Art of Creating Photorealistic Montages - Updated for CS2: Books: Steve Caplin
I know online some people don't like paying for stuff lol but if you're just starting out, one of the few desktop references you should have is that one. You'll learn a lot from it, fast.
Steve Caplin writes some great tutorials!