Because I like the bottom image the best, and because I want to start this critique positively, I'll start there! The guy walking with the board makes the image. The fact that he's been silhouetted against such a nice surf is what makes it a good image.
Be careful with your horizon. In each image, you've slanted the angle of the image contrary to the horizon. Try to not tilt an image each way, unless there's an obvious reason for doing so, or an artistic interpretation that you've obviously trying to make. Otherwise, it just looks crooked, like a camera mistake. Luckily, this can be corrected VERY easily in Photoshop, using the crop tool. When cropping it, you can hover the mouse just outside the crop box corners, and the cursor will form a rotational arrow.
This particular image would also look really nice cropped down to a panoramic image, with the crop happening about halfway between the two groups of clouds.
You could pull some pink and purple out a bit more in Photshop.
That's really a nice scene. Where I live now, I don't even have a decent lake anymore. I'm stuck with mega-sized rivers at best. Although that sounds interesting, they're almost impossible to get to from highways. Shoot it while you're there! You never know when you might move across the country.
I'd consider cropping the image just right of that rock on the left side. It distracts from the subject (the man with the board).
Cloning it out would also be allowed, if this is being done for pure art or illustration. (It would be an unforgivable breach of ethics if it's being used in a journalistic sense.)
- Let's go back to the top image. I'd have to say that's more of a picture than a photograph. A photograph tells a story or has an artistic appeal. A picture just says "I was here" and gives proof in the form of an image.
The biggest tell-tale sign of a "picture" is that it has no definable subject. It just has stuff in the frame. In this case, parts of boats, a sort-of sunset/sunrise, and exposure that isn't great.
- Now compare the middle image to the top one. The middle one is a photograph. The subject is clearly a dock scene, offset by a nice sunset/sunrise. The exposure is set to the scene, not the sun, so the scene is the dominant subject.
The palms in the sun is a nice touch!
Everything falls in place really well in the frame, aside from it being tilted. Unfortunately, I think you may crop into the masts or border elements (like the palms) to re-align the horizon. So as a photo, it's a near miss. It's pretty, will look good in an album, but it won't make a portfolio.
Definitely a good start for you.