Authors often make the mistake of not verifying if there is market demand for their book. Authors who provide evidence of market demand for their book helps show to a literary agent that there is potential demand for their book. Rather than focus just on an outline of their book, it's important to explain WHY it will also sell. Today, this could be by showing the high number of sales already achieved for a previous book, their huge reader base, or (for non-fiction) how popular the subject they are covering is. At kBookPromotions, we take on many self-published authors and pitch them to established publishing houses.
A common mistake authors make when pitching to literary agents is not customizing their submissions to match the agents' specific preferences and requirements. Many send generic query letters that fail to demonstrate an understanding of the agent's tastes and specialties. This lack of personalization often leads to quick dismissals, as agents, overwhelmed with submissions, prioritize pitches that align with their focus on genre, target audience, and thematic content.