Six textbook authors share their textbook proposal writing tips:
"Make sure there is a demand for your book that currently is not being met by exisiting texts."
David J. Ellenbogen, author of Elementary Algebra: Concepts and Applications
"Beware of putting anything in writing too early, since some editors will take your preliminary ideas to be definite proposals. When you do write the proposal, assume it will be your last chance to convince an editor to take an interest in the project. Also keep in mind that no matter how convinced you are that your book will be the best in the field, you have to make that clear to the editor, and you also have to explain to the editor how that is going to be clear to potential adopters."