Restate : the main argument and the conclusion of the essay in a single sentence. As advertising agents say, if you can't write down the idea on the back of a business card, you probably don't have a clear idea. If you can't summarize: the argument in a single-sentence, go back and re-read the essay at Stage II: Interpretive Reading.
Assess your reaction. What convinced you and what did not? Why? How did you respond to the essay as a whole? Why?