I'm with Horoscope Fish on this one. Cropping alone won't do much, but as the others have mentioned, adding some blur to the background will give the impression of a greater DOF. Please excuse my outlining ability--I'm definitely not good when it comes to outlining something with low contrast. I certainly could have done a better job outlining especially near the bottom of the photo as well as with what she is holding, but hopefully you will get the idea.
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And sometimes you have to think outside of the box--literally!!!
This is the first time I ever attempted this effect. Again, whatever the girl is holding posed a problem so I didn't include it here. For this effect, I used PSE 10 and started with the blurred background image above. Then I switched to Guided Edit and added the
Out of Bounds photo effect. You should be able to make this into a useable image utilizing some type of effect--if not this one, then something else.
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