Sometimes we use color, value, edge quality and composition to separate shapes from each other. Sometimes we want to use these variables to combine shapes.
In this scene the background and foreground are squashed together. It would be easier to read the space if some shapes were combined and others were separated. That black and yellow drum, for example, needs to be placed more obviously in the foreground group of shapes. What makes it's location ambiguous?
I usually start with value to see what role that powerful variable plays in both the problem and the solution. Sure enough, the opening of the drum is hard edged and light, just like that shovel handle and the light, horizontal strip of wood. How could the drum or the background shapes be changed to emphasize their differences?
I'd like to see what would happen if I glazed some of the background with a darker wash, swallowing those bright objects in the same shadow that runs along the top. This would be an example of combining shapes to clarify space.
While we're at it, what about further separating the drum from the background by changing it's value and /or color?
If you brought an image home from class, check to see if it lends itself to experimenting with combining and separating shapes. If not, see what you can come up with, or use one of those that follow. There are a couple in the beginning homework from this week, too. In fact, read that whole post. It is quite relevant to your studies.
The basic idea is to use the simplifying effects of combining shapes and separating shapes to make the illusion of space more convincing. Keep track of how you decided which method to use, and be prepared to tell us how well it worked.