A common composing bugaboo for new photographers? With shorter subjects, the tendency is to shoot from above, looking down on them. Among other problems, this higher-than-thou shooting angle introduces unnatural perspective distortion. And the wider the focal length of your lens, the weirder the distortion.
For children, this can result in large heads and relatively tiny feet. When pets are photographed from above, their bodies become as important as their eyes—not good for capturing their personality.