Applying the “rules” of composition, is the first step in improving your photos. Once you understand why a composition works, it is time to go a little deeper into the lay-out of your photographs. This page describes how framing affects your photos.
Don’t mix-up framing and filling the frame though: Framing is creating a frame around the photo, while filling the frame is using as much canvas as needed for your subject.
The reason people like to frame photos and paintings, is not just to protect it. It is also because framing isolates the photo from anything around it, and adds a sense of depth (because you add layers to the photo).
Another function of a frame is, to send the eyes of the viewer directly to the subject and block out any unnecessary elements. Or you could just use a frame to add some drama to the photo.
There are many elements you can use as a frame, and it certainly does not need to rim the entire photo. You could frame just a few empty corners like in the photo below.
You could use the environment to create a narrow view, blocking out parts of the scene, to make the viewer wonder what the photographer is not showing. Or you could take framing literary.
As mentioned, any element you can use to frame the photo, helps viewers to focus their attention at the subject of the picture. Using this in your composition is another great tool to improve your shots. But remember, you do not always have to frame!