The first thing I noticed when looking at this photo is that the paintings in the background are a little distracting. By using the Brush Tool and sampling the colors from the wall it’s easy to simply paint over them and then mask out the subjects. This helps draw attention directly to the focal point and creates a cleaner photo.
Cropping in is a quick fix to balance your composition. Try using the rule of thirds, already visible when you click on the Crop Tool!
Curves Adjustment Layers are great for color toning, as well as brightening the shadows and dark areas of an image. This will make a big difference in your contrast levels. Darkening the edges and adding a vignette will also improve the composition. The vignette makes it seem as if the light was falling directly on the dancers.