Looking at Set 1
For me, #2 is the pick of the three, but I do find my eye wandering off to the left where the beach has been cut off.
Both work as somewhat 'abstract' / generic scenes - the sort of thing that you might find as fairly 'neutral' art in a hotel / conference centre, etc. Calm, gentle tones, to help soothe the minds of busy individuals at the end of a hectic day.
#1 Not sure on this one - I don't think a simple crop would work, as you'd have to 'cut' though some of the rocks, and lose the clean bottom edge to the image.
You could crop the sky somewhat, but there's nothing much in the distance as a main subject.
#2, #3 - I actually prefer #2, the square crop, because of the way the symmetry of the pier and the lighter patch of water - the portrait view crops the water, and you lose this, which I feel weakens the image.
#4 - As Jon mentions, there's definitely potential there, but the foreground seems to take up too much of hte image. perhaps simply cropping some off the bottom might help?
#5 - The lighting shows the bridge structure beautifully, but personally the pier / jetty in the lower left is too intrusive - I'd be tempted to crop a touch off the left, and some off the bottom, to reduce it (possibly keep the aspect ratio and just crop from the lower left corner until it is out of shot?).