Still life with done for students starting with the negative spaces (back ground), saving shapes of subjects. Before it dries, let the background color come in and make the first layers of shadow shapes while blurring contours on subjects (the pot and leaves). We can speed down and lay the colors on objects and if needed reinforce shadows, colors again or even background when dry. Make the main point of interest more obvious by adding contrast in color and contours. (This was a fast demo to get a loose feel of execution and result, the irregular background can be avoided if painting more carefully paying attention to quantity of color, water and paper humidity.) My students tend to be cautious and stiff while painting, this way of painting can help to loosen things up.
Below is the same kind in blue, monochrome still, also done in class a few sessions earlier. Great results and visual effect can be obtained with this exercice and when done without drawing you get the most out of it. Good luck !