Add your own light
Flash will help you to pick out subjects and freeze the action, enabling slightly slower shutter speeds. The important thing is to check beforehand that it’s permitted (or wait and see if any other photographers are using their Speedlights). Your flash will only reach so far in a big venue, so expose for the background first, then use the flash to pick out the subject in the foreground for a balanced exposure. In an enclosed space, try bouncing flash off the wall or ceiling for softer results and even illumination. You could also try using slow sync flash (done by lowering the shutter speed) for creative blur effects.