Composing a picture is about more than just putting your subject inside the frame. This video shows you the basics of photo composition so you can learn to take better photos.
The video, from previously-featured photography channel COOPH gives several examples of nine different "rules" including the rule of thirds, using leading lines, natural frames, and more. Obviously you can't do all of them in a single photo all of the time, and the video is quick to remind you that rules are meant to be broken. However, keeping these principles in mind can help you take better pictures.