This kid allowed me a few seconds of motionlessness. Only a few. At least he actually looked at the camera during those few and far between seconds.
The softer colors work well for children. Harsh colors and sharp edges conflict with their so called "innocence". I wasn't as much a fan of this shot as my wife seems to be...it's a tad too centered for my liking. But hey, he's cute.
I think the best shots of children are taken when they are busy doing something besides posing. A nice 85mm lens will catch the emotion of the situation without having to include the slobbery sippy cup or the stained and shredded stuffed animal they've had forever. Sometimes I disregard this entirely. That stained stuffed animal might be their favorite toy and should definitely be a part of the photo.