I confess I don't always take the short time needed to consider the value pattern and the composition before launching into a first attempt, but I know (and you know) that it makes good sense.
In less than 5 minutes, you can try out several variations of placement and relative values of the major shapes.
|Unloading the brick kiln, San Agustine Yatareni, Oaxaca
What if The narrow shape of the opening were much darker, so that the worker (Jose) stood out more? Or, would it be better to make Jose darker, so he seems more enveloped by the opening? Both options can be tested with a pencil and a scrap of paper, and two minutes time.
Look for an image that has a few overlapping shapes, or use one of these, and consider what you might change to enhance the sense of space, or simply to enliven the picture plane. Bring in your sketches, and the photo, if you can. Feel free to paint the scene, once you've made your decisions.