Composition is a huge subject, I'm only mentioning topics that make quick tips. I'll talk later about the rule-of-thirds, which most photographers a familiar with. But first I'll mention placing the subject at the edge of a photograph for effect.
While this isn't a technique that works very often, sometimes placing a subject at the edge can make the viewer spend just a little more time with the photo, and create a little visual tension. Here I placed the singer near the edge, in part, to give more prominence to the background, which was the banner advertising the Lotus Music Festival. I also changed the colors to a sepia look, since the stage lighting gave a distracting color cast.