Interaction designer @ Google. Loves soup, soccer, and the outdoors.
…e, if you find yourself needing to erase a set of buttons, explain the reasoning behind the change. Mistakes are fine; acknowledge them. It shows that you are not wedded to your first design.
…quickly reference the main flows into user states (rectangles) and user decision points (diamonds). Begin to check off the design story flow as you progress through your task flow. Using the check boxes will prevent you from forgetting to address the edge or corner cases in your task flow.
Demonstrate that you are thinking about potential problems. In summary: write down the main flow and alternate flows, make mention of edge and corner cases.