This tutorial is going to show you how to take an ordinary photo and change the background to accomplish all these purposes.
Start with a photo that has a clearly defined foreground image.
Duplicate the layer by dragging to the new layer icon.
Use the extract tool to knock out the foreground image. (Details of this in another tutorial)
Sometimes the extract tool gets a bit over zealous. Hide the background. Use the history brush and eraser to clean up and cut out image.
Here is our image with the background removed. Note, its still intact in the background layer.
Now hide the cutout layer. Show the background layer and choose the bg as our working layer. Filter> blur> motion blur. Play with the settings until you find something you like.
To add a bit of pizzazz, Duplicate the layer, Invert it (cmd/ctrl+I) and change it to Luminosity mode.
See how it looks now.
We can soften the effect by applying a radial blur to the duplicated layer. Filter>blur>radial blur
The result is much more appealing.
If you wish you could apply a soft drop shadow to highlight the subject a bit more. Use it in such a manner as it looks more like an outer glow.
Another variation would be to apply a soft outer glow.