Conwy Falls

The waterfall is such a small part of the frame; you might try some shots that have the waterfall as a much more significant component.  Try some different shutter speeds as well that will show addition structure in the waterfall.  Often there is a narrow range of speeds that represent a very nice compromise between structure and the sense of flow.  You might have to consider two blended exposures to accommodate the light difference between the white water and the surrounding vegetation.

Beautiful place.  Not knowing what is to the left, and the depth of the water, I agree with Stephen in that I would go for a longer shutter speed. 

You might also try wading out into the water, setup your tripod, and focus on the white foam/streaks in the water.  I've had some cool waterfall shots where those water streaks making really interesting paterns.

I would also change the time of day for the shoot, maybe early or late day to get a little more interesting lighting in the scene.

-Jon