I found these aging blackberry leaves very attractive because of their vivid colors. The dark background gives the image a chiaroscuro effect. Also, the twigs create lines going almost perfectly to the four corners of the picture.
To achieve the chiaroscuro effect in-camera (and because the photo was taken on a bright, sunny day) I used a combination of a large lens aperture and a fast shutter speed. Sharpening was later enhanced in Adobe Camera Raw.
Technical data: aperture f/4.0, exposure 1/500th sec, ISO 100.