This is my Dad last year at my Gran's 99th birthday meal. The room we were in was well lit but I don't think I had the 50mm lens then so the shutter speed was a little too long to be sharp. I'm not good at using flash indoors, I have the SB600 but I just don't use it properly. I also find in situations like this that the strength of the flash needed depends on how near you are to the subject and I forget to change the strength as I move around. Ad astra per aspera
However, you would probably have lost that reflection because the exposure would have been too high for it.
This guy is pretty good for on-camera flash technique.
But of course it all depends on the 'raydiosity' of the environment. You can't be me, I'm taken
For something like this I'd probably try bouncing it backwards and using the whole back wall as a diffuser. This confuses metering, so sometimes you have to set the exposure manually.
You can also buy clip-on diffusers which work fairly well and remove some of the hard edges, stark shadows and flattening.
Hand held flash can also work. Close the shutter as far as it goes, open it with a bulb setting for a second or two to add some ambience and movement blur, and manually fire the flash off the back wall.
Buying a crossbar support for the flash to move it off the lens axis also makes a bit of a difference. As a last resort you can use loo paper as a very cheap diffuser, but that's another good way to confuse the exposure metering.
Hey, Grandma Moses started late!
Another option would be to make a copy of the photo [duplicate] as a new layer and then knock out the sky in the top layer, using a mask.
This will enable you to apply curves and effects to sky and building independently.
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I've been preoccupied with a family member who's not well. :-(
It helps if you incresase the contrast a bit as well.
Second, I think the colour is distracting from the shadows and shapes:
Here's the histogram before any adjustments:
The bottom axis is brightness, black to white from left to right. The height axis shows what proportion of the picture is that brightness. So this shows that there are only light tones, no solid blacks or even really dark greys in the picture. This is normally a bad thing. (Except when it's not, of course - that's a judgement to make.)
So, we use auto-levels and get this:
Now there are areas of every brightness in the image, which normally looks more natural: our eyes adjust in roughly that way. How you adjust the levels depends on what tool you're using of course - you can fine tune it with a lot of them.
As a rule of thumb, if what's good about a picture is the light and shade, it may be worth trying in B&W.