One of our favorite Photography blogs to read is The Tamron Blog.
Here are 6 points David Akoubian makes about taking the perfect waterfall or river images:

1. Contrast can make or break an image
“The best time to shoot flowing water is on a low contrast day whether it is a result of an overcast day or even just after a rain or drizzle.”
2. Slow shutter speed gives you that soft-flowing water look
“The other advantage to shooting in low contrast is that you are able to shoot at f11 or f16 and still get a shutter speed of 1 second or slower to give the water a soft flowing look.”
3. Use a tripod, especially with slow shutter speeds
“My tripod of choice is the Vanguard Abeo or Alta Pro tripod. I have used this tripod in extremely awkward positions, often while standing in knee or waist deep water. The tripod legs will go to ground level independently and I will often have two legs resting on a wall or rock almost making the setup a right angle!”
4. Get a high-quality circular polarizer
“The polarizer is going to eliminate glare from foliage and the rocks around the river while adding some contrast to the scene to make the compositional elements stand out more.”
5. Squinting can help you visualize and imagine how your photo will look at slow shutter speeds (cool trick!!!)
“In order to pre-visualize the effect of the slow shutter speeds I will squint. This makes the flow apparent to a minor extent.”
6. Be creative with shape, and use nature to show depth
“Shooting waterfalls is usually done from an obvious point but when photographing rivers I will try and find some area that has nice “C” or “S” curves in the river. I will also look for objects such as flowers or ferns to place into the foreground.”
Isn’t that interesting? You should definitely check out the blog!!