Part of the fun of representational painting is the illusion of depth. The red onion and the pitcher are in front of the shelf with the bright fruit and the vase, and I wanted to really show that. How to make that happen? Part of it is the linear perspective. Part of it is overlapping the pitcher over the shelf and onion.
Another part is the atmospheric perspective. Atmospheric perspective is the visual feel of "air" between the viewer and an object. The air can make colors cooler, grayer, and it can reduce contrast.
This time I wanted the fruit to be warm and bright, and the background to also be a warm color... that left me with contrast as the only way to show atmospheric perspective. To make that happen, I saved my real darks and lights for the pitcher and onion in the foreground.
So far, I've developed depth, light and form. Next will come surface decoration and highlights. Note that the surface decoration and details will come last!