Photography comes from the greek root words for light and drawing. Understanding lighting is one of the key aspects to getting good images. Children can be difficult to photograph because they move around so much it is difficult to get the exact lighting your want on them. To guarantee you will get great images of your kids, even when they move and play, have them be in an area light with soft light. This could be outdoors in the shade or indoors next to a large window. The bigger the light source the softer the light. Also make sure the area you are in isn’t to dark. If you are in a dark area you’re camera will need to use a longer shutter speed to take the image. If you use to long of a shutter speed the image can end up blurry especially if your kid is moving.