Creating a watercolor effect is one of the many ways you can stylize your images and it is easier than you think.
First select a photo in the Library, make sure the photo is not in high-resolution. Because this technique works best for low resolution images no more than 1000 pixels on the long edge. If your photo is in high resolution, you can export a copy in lower resolution.
Now that you have selected the image, go to the Adjustment module and in the Global Adjustment Tools:
- Set Contrast to 50
- Dark to 100
- Vibrance to 50
- Saturation to 50
In the Detail section, set Luminance to 100 and Detail to 50.
And there you have the watercolor version of your photo.
You can make further fine tune adjustment in order to reach the look you want. In this example, I partially selected the background trees and reduce the clarity.
And here is the final image: