First Three Chapters
The first three chapters is the section of the proposal where you can wow the agent or editor with your writing ability. Your platform is very important, but the writing and the story supersede everything (writing is king!). They are looking for something that grabs their attention and holds it—something they can enthusiastically represent and try to sell. Your writing MUST shine. There are oodles of good books out there, and plenty of very good ones. To catch the eye of an agent, and later an editor, your book needs to be excellent. It must stand head and shoulders over the average submission they review.
Make sure your first three chapters (often the first 50 pages):
1) Hook the reader in the first few paragraphs.
2) Don’t include any backstory in the first chapter, and very little backstory in the rest of the submission.
3) Don’t include any information dumps.
4) Don’t include episodic scenes that just get the characters from one important scene to the next. Make sure every scene has a reason for being there that moves the story forward.
5) Contain good spelling and punctuation.
Double- and triple-check the above items. Let other people review them (particularly others who write; better yet, critique partners). Make everything as perfect as possible. You don’t want to give the agent or editor any reason to stop reading.