The best way to get a shot like this with kids is to be friendly and fun. Kids won’t be rushed, and they look much less happy and relaxed if you are trying to boss them around. It takes longer, but it is worth the effort.
If you are taking pictures of your own kids, be prepared for the first hour to not be nearly as good as the second hour.
Photo © Alex Schoenfeldt, 2011
San Francisco Bay Area Photographer