Get Closer to Your Subject
Almost any shot will look better if you take two or three steps closer to your subject. Filling the frame entirely with your subject will make a terrific difference to your photos.
Alternatively, instead of moving closer, use the Optical Zoom of your camera to get a close up shot. Don't use your Digital Zoom as it will degrade your image quality.
When taking shots of family and friends, most people place the subject's full body in the frame, or place head and arms in the shot. Instead, fill the frame with your subject's FACE only - particularly if they are smiling or are in a moment of reflection.
Why does this work? With less clutter in the image, there's less to draw the eye away from the main subject of your photo. Also, human faces (particularly children's faces) are something we all feel pleasure looking at.
If you can't get close enough when you're taking the shot, you can zoom in later using photo editing software - crop out everything except the subject's face and see what a difference it makes.
When using the viewfinder for close shots, be careful of Parallax. Because the viewfinder is not at the same position as the camera's lens, centering the subject in the viewfinder may mean it is not centered for the lens resulting in an off-center final picture. Most digital cameras now come with an inbuilt LCD screen. You can eliminate this problem by using the LCD - which shows you what the lens sees - rather than the viewfinder.