Hi Sandy
I'm echoing the others a bit here
1. It's not working at all well I'm afraid, this technique works in some cases but not for you here, normally used to accentuate some feature or a focal point. Sorry that looks like a bad day when I forgot to focus
Maybe just maybe if the focus was on the falls?
2. This as was said above has a serious case of wonk. I really notice this as it's something I suffer with time to time think about getting one of those silly levels that sits on the hot shoe if you get this often, or perhaps your camera has a built in horizon you can use. Of course you can always correct this in post processing but you always loose some of your photo. Also as above you have some naughty blown areas
Where the whites have blown all detail out of the image, Top sun, left waterfall and foreground reflection, your camera should have blinkys on its histogram menu this will show you where the blown highlights are, always check the histogram after the shot this will tell you if you need to take the shot again before leaving the location.
3. I'm with Nod on this one just crop a bit off the bottom edge. I think this is possibly the best shot here I like the light through the wood on the left there's better light across the top of the falls and you can see the pool of the water fall bit wider perhaps if your lens could accommodate maybe.
4. Not a bad shot, with better lighting I don't like that you can't see the pool from the waterfall so for me a slightly higher or closer perspective would have worked better for me. I'd say this might have been my pick if the pool was in view as the lights much better. I know sometimes it's not possible to get that composition where you want it due to the constraints of your lens or you can't physically get where you want to take the shot from, but that's all part of the game
.
It's a learning curve and were all still doing that!
Hope this helped a tiny bit
All the best Steve