Whenever you take on a new scene or image as a painting subject, it's a very good idea to consider what might pose a problem for you. Wherever you are in your skill development, you can tell in your gut what will translate gracefully and what will require some practice. The hard part is remembering to take a little time to assess your readiness.
In this picture, for example, I can foresee some trouble getting the mass of green that surrounds the sheep to be a smooth, clean wash. With all the care I might choose to take painting around the sheep I could end up with streaky, overlapping brushstrokes. This is the kind of problem I could easily overlook, though, since the grass is not the real subject of the scene. My attention goes right to the sheep, so I'd probably consider how to paint them first. If I feel confident about translating them into layers, I'd think, "OK, I'm ready to paint". Then, when I got to the grass, I'd discover too late that I was not as confident about that part.
Five minutes is plenty of time to devote to an honest assessment of what may be tricky for you, and to devise a study that will give you the answers and the practice that you need. If you are concerned about undoing your precious spontaneity, you needn't be. A little practice will not turn the process into a dry, cerebral activity. As soon as you make a stroke on a new sheet of paper the juices will start to flow. The only difference is that you'll be more confident, and won't have to shift gears for the tricky bit.
By the way, if you paint this picture, consider moving that fence post.
Here are a couple of images to think about.
The homework is mostly about the task of identifying the nature of the unanswered question. Is it about value, color, wetness or composition? Once you decide, you can isolate that variable to find your answer most efficiently. So far, in class, we've looked mostly at wetness, or edge quality as a variable. If you decided that your question was about value, perhaps a monochrome value study would provide the information you need. If you were wondering where in the sequence of layers you needed to make sure the content was identifiable, it would be useful to make a quick version of just the strong darks in the scene, to find out how much of the story they tell. As the course progresses we will make this kind of assessment many times.
Please be prepared to tell the group what your unanswered question was, and how you attempted to answer it. If you have time to paint the picture, so much the better. Bring that, too.In the example of the sheep in the meadow, the unanswered question is, "how can I paint the meadow as a fluid, continuous wash and still paint around the sheep?" It would probably not be necessary to paint the whole picture to answer this. It seems to be a wetness issue, so practicing painting around a shape with varying degrees of wetness on the paper and brush would reveal a good approach.