how to hold a flatpick

How should I hold a flatpick?  I've heard that the strumming/picking hand should look as if it's holding a dandelion gone to seed.  When I'm watching really good players, their pick hand seems to float over the strings, the pick can barely be seen, and the tip seems to be pointing slightly toward the palm.  I've been trying that recently instead of my usual style, which is to clutch the pick between thumb and forefinger with the tip pointing slightly outward, away from the palm, and all my fingers quite rigid.  Any suggestions?