Shot 1 - Pretty nice, well done!
Shot 2 - A big pair of feet in the water and nothing else! You gotta love the GoPro tiny focal length...
When you're doing half-in/half-out shots, make sure the horizon is level, by which I mean that you can't see the surface of the water, otherwise there's a weird "where's the foreground?" effect.
Shot 3 - Nice effect with the water, but the tiny surfer in the background is distracting. Also, the focus is on the surfer/background, when it should have been on the water (but that's more or less impossible to control with a GoPro).
Would have been a better photograph without the surfer... and also if the water had been less green and icky!
