Sometimes software really impresses me. I have talked a lot about ProCamera+, but there is another photography app that seems to perform miracles and that is Nightcappro. There is a free version Nightcap that allows you to get a taste of what the app can achieve.
For the above shot (click on photo to be taken to the original), I changed the settings in Nightcappro to long exposure mode, placed my iPhone 6S Plus on my tripod. My iPhone is attached to the tripod using a Shoulderpod S1. I then increased the photo quality to raw (TIFF).I then pressed the shutter button and watched the time increase and the photo start to create the silky water effect. 45.29 seconds later I stopped the shutter and voila. A perfect shot!
To see more of what Nightcap app can produce, have a look at the developers gallery.