Burn Your Photo's Edges
Back in the days of film and darkrooms, you could control the look of your prints with techniques called "dodging" and "burning." As you exposed a print, for example, you could cover part of the photographic paper on which you were exposing the image. The resulting effect (dodging) would make the obscured section lighter than the rest of the image. Alternately, you could expose another section of the photo longer (burning), and that would make it darker. Burn part of the photo long enough, and it would turn black.
Digitally, you can apply the burn effect to add some subtle vignetting to a photo. You can work with any image, but it helps to start with one that is already predominantly dark overall, like this shot of my son's marching band taken at a nighttime football game. You want to focus on the middle of the image by gradually darkening both sides, until the left and right edges are pure black. I'll show you an easy method that relies on the Photoshop Elements Levels tool.