In addition to concentrating on the writing, just keep the content simple with minimal markup if possible so that it's easy to rejig later if needs be. People

In addition to concentrating on the writing, just keep the content simple with minimal markup if possible so that it's easy to rejig later if needs be. People rag on Amazon, but as a book buyer it's nice to have all your books in one place on a platform that's likely to be around next year, rather than random PDF's that end up who knows where. It's also nice that the book is subjected to reviews. Those can be capricious and unfair at times, but if there are enough, you get a better sense of the book than "Buy it! Trust me!".