Reread the passage by Mary Sarton on pages 54-55 of your textbook. What other activities do you participate in that could be compared to drafting? Write in your journal about different forms of "drafting" you do every day. What processes do you follow?
Practice writing descriptive outlines, using published essays as prompts. For each essay, number the paragraphs and write down for each number (a) what each paragraph says and (b) what each paragraph does (see page 63 in your textbook).
You could try the following newspaper websites, which allow you to read their editorials without registering:
The websites of major newspapers such as the New York Times, Washington Post, and major e-zines such as Salon and Slate are good essay sources but require registration (which is free).