One of the questions I get asked the most is how do you get the water to look all silky like it's moving. The answer is easy, a slow shutter speed. Here are a few quick tips that will help you show some movement in your water scape's.
First you will need a tripod and if you have one a remote release, due to the slow shutter speed you will need to remove any chance of shaking the camera.
Set your camera to aperture priority and choose a smaller F-Stop say F13 - F22 by doing this the camera will automatically reduce the shutter speed.
If in bright light light set you ISO to 100 or 200 this will also make the camera reduce the shutter speed.
Avoid bright days or shoot early in the morning or late in the evening, by doing this you will automatically have less available light to work with and this also will force the camera to set a slower shutter speed.
Nothing beets trial and error so get out their and point at some moving water, most likely you will be happy with the results.