Write about one of those wonderful times when you felt ON, when everything worked and you were moving ahead full speed.
Have you ever felt you were just a piece of a big puzzle, or a cog in a wheel. Describe the situation, including all your feelings and sensations. What happened to make you feel this way, and how did you change?
Write about something or some time when you feel exceedingly slow. Describe all your emotions and take your time to make the reader feel your writing dawdles and nearly stops to a stand still.