Here's the final image. I don't think it needs much more work than this -- if I have
to look for something to do, I would think the building in the background, and
the shadows on the ground are a bit diffuse for a blue sky day. So maybe a bit more contrast
might make it look like a sunnier day. But when I played with contrast, it's easy to get
the people looking too harsh, so I think you'll need to be careful with contrast.