Frames can be basically any item that encloses or surrounds your subject. This could be branches of nearby trees or even a solid frame such as a cut-out in a wall. Take note of your surroundings, and keep an eye out for objects that would make for an image-enhancing 'frame'.

Take shape, texture, and color into consideration, frames which contrast sharply with the subject of your picture can make for beautiful photographs. Use frames with care, as misuse can create cluttered or visually unappealing pictures.

A good example of framing, this picture would be rather bland without the frame. With it, however, it is a stunning picture.

Here's another good example of framing: