Vignette

The image on the top is the new and modified image and the image on the bottom is the original image. Start with the elliptical marquee tool and draw an ellipse or circle on the area you want to focus on. then invert the selection and change the brightness so anything on the outside of the shape will turn darker. Then to darken it farther make a copy of the original layer and add a layer mask in which you will draw in with the brush tool (make sure you are using black as the foreground color.) Afterwards use the gradient tool and hit the circle selection to make a circle and change the layer mode to soft light or overlay and lastly change the opacity to 50%. Finally, if you really desire to add attraction to the center of the image or circle use the burn  and dodge tools.