We’ll mostly use the blank paper surface to represent the reflected light of the sky, and we won’t shade the water surface much at all, except in shadow.
01. Think in planes
Start by mentally breaking down the water in the scene into two components: the reflections or shadows of objects moving ‘vertically’ down your image, and the sky light being reflected on the surface turbulence.
Visualising the two main planes in a water scene will help you construct the image. Objects such as trees, rocks and boats reflect and stretch/smear down vertically. Sky-light reflections lay horizontally across the water surface, on top of the vertical elements, breaking them up.
The more turbulent the surface, the more complex the skylight reflections. With calmer water, everything is simplified. You can adjust this complexity as you prefer.
02. Develop the scene
As an exercise, I tried building a scene with a rocky lake floor. When adding this detail, those values all need to stay in a narrow range, subdued by the water over them. However, I wanted to simplify detail in my final design, so I decided to use objects above the water surface instead.
03. Smear the shadows
This is my warm-up boat sketch. I smeared the boat hull down into its shadow in the water, and looked for ways to indicate the plane of the water surface using minimal detail.
04. Enhance the scene with details
I realised the composition was too boring, and decided to use water lily clusters rather than ripples to describe the water surface. The water lilies could also be freely arranged to best serve my composition. I used a kneaded eraser to lift out any pads that I wanted to pop a bit more.
I also let the shading of the boat hull flow down into the boat’s shadow on the water, and cross over that with the horizontally arranged pads.