For simplicity's sake, I've converted your image to B&W to demonstrate a few things (so mind the compression):
That histogram is pretty bunched up to the right for a day shot, eh? Let's see how much of that is clipping:
Ouch! The brightness seemed quite painful to my eyes and now we can see exactly how bad it is.
So let's edit that a bit:
And now we have a histogram that's mildly more sane. This is by no means perfect, but it should give you an idea as to what is a more sensible lighting setup for a scene.