Look at structure. What is the ad trying to sell? How is it trying to sell the product? What text is in the piece and why has it been included? What pictures are in the piece and why were they included? What is the feel of the ad and how does it help sell the product? (e.g. colours used) :wave:
What i found that helped me when i needed to revise was that you highlight the first and last sentence of each paragraph and that usually will help you