The sample chapter might seem like a pointless exercise to a new author, even more so to an experienced author. After all, if you’ve written an acceptable proposal, surely you’ve proven to your acquisitions editor that you have good writing skills. Why do they need a sample chapter?
First of all, the sample chapter will help you (the author) determine if you can write to the series guidelines/template provided by the editor. You might be a great writer, but do you have the skills to write to the appropriate audience? Are you able to deliver on all the key elements in the series? Are you able to provide the right amount of material for each topic in the chapter?
Second, if you’ve never written a book before, you’ll see how long it takes to write a chapter. You ought to be able to extrapolate from that to determine a reasonable, and realistic, writing schedule for the entire book. If it takes you a week to write the sample, don’t assume you’ll be able to write each subsequent chapter in 2 days or less. Also, don’t let your acquisitions editor bully you into thinking you’ll be able to write faster. You know your schedule, your other commitments, etc., better than anyone else.
Use the sample chapter to your advantage. Insist on detailed feedback from the acquisitions editor and/or a development editor. If you’re going to invest your time in a sample chapter, the least they can do is give it a thorough review and help coach you. Be very skeptical if the editor simply says, “hey, it looked great…we don’t have any comments…keep writing!” This could be a warning signal that nobody had the time to look it over and they’re anxious to hit the next manuscript delivery date on the schedule. That could mean a lot of rework for you and the editor down the road.
By the way, be sure to keep track of the amount of time you have to spend reworking the sample chapter to address the editor’s feedback. This will help you gauge the amount of work you’ll be faced with at the author review stage for the rest of the manuscript. However, if the editor does a good job providing high-level feedback, you should incorporate that feedback in the later chapters, making for less author review work down the road.