hi,
these are very general snap shots the first thing that comes to mind is that there is no particular subject that strikes me. the next thing is that there is no contrast in the pictures at all. looks totally flat, like a scanned picture.
what kind of photography are you interested in? looking in to that matter will help you focus and hone your skills.
in picture 1,
i guess you wanted to shoot the dolphin.
you could get closer to it and concenntrate on the animal and have less background. it helps to isolate the item of interest if there are less distractions available. unless of course the other objects in the picture serve other purposes.