Painting a new subject can be a steep uphill climb. It usually takes more than one piece of paper before I begin to know what is essential and what is optional. Understanding a subject in terms of washes and strokes requires knowing it intimately –memorizing it, in a way.
This exercise is designed to bring you to the place where you know your subject well enough not to need to even look at it.
Choose a simple subject. I recommend something shiny, like a persimmon, or a tea kettle, and not too elaborate.
Take all the time you want on the first version. Go ahead and paint LOTS of information. Then paint it again. And again. And so on, until you know what needs to be in the painting and what you can let go of.
Now put the object out of sight, and paint one from your understanding of the essential elements.