One of the things that happens a lot when I'm photographing families is I'll send the kids out to run around a little bit to get better photos. In my right ear, I suddenly hear mum and dad screaming "Hey, get back here; Don't do that; Stop doing that." The problem with this is that as soon as kids feel that their imagination is stifled, the fun stops and the photos don't turn out as well. When you're photographing kids, say yes to everything. Let them run amok.
Give them a 1-hour-free pass. Here in this photo, we had a brother that wanted to put his little sisters upside-down. Mum was initially, "No, they'll get hurt," and I was, "Hey, we're insured." At the end of the day, the more fun the kids have, the better the photos will turn out. Say yes to everything. The other thing to keep in mind when photographing kids at play is to let their imaginations run rampant. Sometimes, it's not enough to say yes.
You have to foster it. Ask questions. Get them thinking. Get them exploring. The more activities the kids are involved with while they are being photographed, the more stories are going to come out. Whenever families bring their kids into me to be photographed; before I even pull out the camera, I'm playing with Barbie dolls, I'm playing with cars and trucks. I'm having tea parties and mud pies for a good 20 minutes. What we want to do is foster that imagination. We want to say yes to everything the kid wants to do and we want to create that relationship with them so it comes out in the photographs.