While finishing editing my manuscript, I also started drafting some promotional material--a query letter, synopsis, and most recently, a one sheet.
Now, the specifications for a "one sheet" (a one-page document used to pitch to agents and editors personally) don't seem to be as rigid as those for preparing a manuscript. But most one sheets I've seen contain the following elements.
A tag line. One brief sentence attempting to get the agent's attention.
A brief synopsis or "hook." A few sentences introducing the plot of the book, much like one would include in a good, concise query letter.
A brief bio of the author and his or her writing history. This was hard for me. I'm not used to writing about myself.
A photograph. Even harder. I hate having pictures taken. I might need to get a professional portrait done.
Contact information. Double checking for typos.
Unlike manuscript preparation, some creativity is allowed--the use of a frame, layout, even a tiny splash of color.
Bad ideas? Colored paper, glitter, unusual fonts, too much clip art. In short, anything that says 'tacky' or 'unprofessional.'