Information in a query letter to a publisher should include an address to the agent by name, what is interesting about the work and a summary of the story. The letter should also include why the author chose that specific agent and any social platforms the author may have.
Include the agent's name in the letter's salutation, and make sure you spell it correctly. This personalizes the letter, shows that you researched the agent or agency and helps the agent take the letter more seriously. The first paragraph should not introduce the author, but rather the work. It needs to include the main theme, conflict, storyline or purpose of the work.
Follow the introduction by a brief summary of the work. This should resemble the summaries written on the back cover of a book and be one to two paragraphs in length. This is the most important section of the letter, and as such, needs to be focused and articulate.
Next, explain what it is about the agent that interests you the most. If there are other similar published works for which the agent is responsible, highlight them. Argue why you believe your work fits into the same category as the work the agent typically represents. Conclude the letter with personal information and details about any speaking engagements, websites or social media pages.