1. The Title of your work.
2. Your contact information. (And your agent's if applicable.)
3. An author bio.
4. Your picture. (It helps the editor/agent to put a face with a name, and it might help them remember you when they get home and look through all their pitch sheets.)
5. A brief synopsis of your work.
Five things NOT to put on your pitch sheet:
1. An endorsement from your mother.
2. Promises that this book will sell 100,000 copies in the first month of release.
3. The phrase "God told me you would buy this book."
4. Any chainmail type threats, i.e. "You will have four thousand years of bad luck if you turn down this manuscript."
5. An obnoxious color or font that is hard to read...like mustard yellow.
The above picture is of a lake steamer that I included in the upper left corner of my pitch sheet last year, as it tied in directly with my story.