"All kids need is a little help, a little hope, and somebody that believes in them."
I don't have any kids, but I seem to be pretty good with them when it comes to capturing them being them. I can't emphasize enough how important it is to let kids be kids while you photograph them. Let them be who they are, and be quick on the shutter button to capture it at just the right moment. Some can take direction well, but most are not able to put on a believable fake smile, so it's better to capture them with no smile at all if you can't get a real one out of them. I strive to make my photo shoots fun for kids when I'm photographing them, and may even get down on the ground, on their level and stop shooting all together for a bit just to get them more comfortable with the strange guy that's got a big camera all up in their grill.