Well... ND filter is important for some of the shots... like making water smooth and silky because due to slower shutter speed and stuff like that. But at present moment, no need to get this type of equipment yet. My advise is to work on your composition and exposure first.
One of the more difficult shot would be the white flower, because it will easily go overexpose. In my case, I always manually step down exposure in order to achieve a correct exposure for the flower itself, since the flower is my main subject.
As for the last photo, I think there are some motion blur (photo a bit small, so cannot really tell, but I think the cranes look abit blurry as in not the same blur as unfocused objects but motion blur).
Like what others had said, step down your ISO (maybe to ISO 100 or so). I would also advise that you use aperture priority in this case, so you only need to concentrate on 1 variable at a time and not jump too fast into Manual control.