From the Open Textbook Network - a manual to help you edit or remix an existing open textbook to fit the needs of your class.
From the Open Textbook Network, a manual for creating your own open textbooks to share with others. Click on the book cover to go to the page where you can download the manual.
From the Center for Media & Social Impact, and the American University Washington College of Law, here is a Code of Best Practices in Fair Use for Open Educational Resources: A Guide for Authors, Adapters & Adopters of Openly Licensed Teaching and Learning Materials to help you navigate fairly using the work of others when you author or adapt an OER.
A note from their CC license page: "While we have released this code under an open license for the widest possible reuse, please be aware that the principles are carefully crafted to be read together and reflect the series of workshops and interviews that informed the Code. Please make clear when you are using only an excerpt, and carefully note if you are making any changes or alternations not in the original code."