Drawing a photograph with the aid of a Grid is a common technique for making copyinng easier, although it's also sometimes used as a teaching tool for early artists.

I'm not in love with this explanation (Loomis does much better) but this should give you the essential idea:

http://drawsketch.about.com/od/drawinglessonsandtips/ss/griddrawing.htm

As a teaching tool for people who can't draw, I haven't seen it be effective, but it's awesome if you've got a deadline and don't want to spend all your time checking and rechecking your proportions.I doubt it would be effective, since it's so easy for novice artists to screw up when they have the image right in front of them.

There's a more effective method which uses a ruler or compass and is often used to copy Bargue drawings. Use precise measurements around a line at the meridian and essentially connect the dots. For the curious:

http://conceptart.org/forums/showthread.php?t=121170

This might work long distance: "Okay, draw the next dot 9/32nds of an inch a way at 12 degrees down to the right."

This still seems like a bit of a cop out, though. Yes, there are ways to assemble copies of images using a grid, but it doesn't help us figure out how such freehand images were made in the first place. We're not even taking a crack at the little black box.