They're all a little overexposed IMO, but the first one's the best - your camera might have bracketing, which would help you figure out which settings provide the best exposures.
On the first two, I'd try setting ISO to maybe 200 (not sure what you're using) and try using f/8 or f/11 in aperture priority mode and metering off the rocks. That would be where I'd start anyway. Then maybe increase shutter speed from there.
The first one's the best for exposure; I would have put the "v" of the rocks just a bit more to the right, but the composure's still pretty good. I love shots like this, with sky, water, and interesting stuff between them.
On the last one, I would have set the exposure by metering off the rocks instead of the sky. That would have brought out the detail in the rocks more, though the sky would have probably been overexposed a bit.
My 2c as a newbie.