This illustration is one of the artworks for the playing cards of a board game that is being designed by a friend of mine.
In the game it can occur that trading routes become untraversable due to heavy storms. This picture shows the crewman of a freighter struggling with this very problem.
This artwork focuses on reflections and surface structures, like the clouds, the wet floor of the deck and the water.
This might be interesting for you as well:
On of the roles of the composition of an image is to depict the most important elements of the picture in a clear, recognizable manner. For color pictures, not only the placement of the elements is playing a central role, but the color composition as well.
An obvious method is to separate diffrent elements or layers within the image like foreground and background by different color saturations of a difference in lightness.
There are many approaches for setting up a color composition. To acquire some helpful rules of thumb, it can be useful to look at some of the oldest works of visual design in history: Coat of arms and flags.