Internalizing Lytro light field photography techniques can take time and practice, but there's an easy one that you can master in no time at all. Get a friend to hold an interesting object out in front of him and take a picture, holding your camera really close to the object. We call this picture "the present" (as in the verb, not the noun). Here's a living picture of Alex, one of Lytro's handsome designers, presenting his friend's band's CD:
Here's a picture of me taking that shot. I'm zoomed out all the way (full wide), and the front of my camera is about 4" away from the CD. Note that 4" means 4"—not 6", 8" or 12". I've had Alex tilt the CD so it takes up less of the frame.
You can shoot from further away and still get great refocus by moving backward and zooming in. Here's a shot taken at about 2x zoom (just over half zoomed in everyday mode).
Here's a picture of me taking that picture. I'm zoomed in just over half way in everyday mode (about 2x).
Mastering "the present" gives you an easy way to take highly-refocusable living pictures of your friends. Give it a try!