If you are with a traditional, royalty-paying publisher, your book will already have been edited. The publisher may do the conversions to E-book for you, including a cover and an internationally recognised reference number. Your book can easily be located because it will be on their website as well as your own. Expect 25% under this system.
You may prefer to take your out of print books and do the work of converting to E-books yourself. You will get a higher percentage from Amazon – 70% – but you will be responsible for the editing, for the work of transferring the text, for the cover, and for obtaining an internationally recognised reference number. However, if you price your book low at, say, $2.99 or less, you will not get the full 70% but more like 35%.
If you want to transfer your backlist yourself, check your contracts with a publisher before you start work. If the publisher has let your book go out of print, ask them for a reversion of rights and for the pdf file. This may take some time to do.
If you want to do it yourself:
Make sure your book is as good as you can possibly make it. Spend money on a good editor. Buy an appropriate cover, and price your book correctly – usually just under the cost of a paperback. There seems to be some benefit from setting the initial price low and then putting it up after a while. A number of firms have sprung up offering their services to put your mss onto E for you. They will make a charge for this. This is another form of self-publishing, and it has the same limitation – i.e., how does a buyer know you are there?
If your work is not good enough for a royalty-paying publisher, it will probably fail as an E-book.
In either case, how do you get people to find your books?
Cultivate your tribe – that is your following of readers – through a professional website, newsletters, blogs, and writers’ loops. Use the Amazon Authors’ pages. Post on your website frequently, and invite other people to comment – and then you comment on what they’ve written. Share your blog with other writers of like minds, which expands your readership. Offer freebies for a limited period of time. If you send out a newsletter, make sure the content is writing-orientated. Facebook and Twitter may take up a lot of your time but it is not yet proven that they lead to sales.
However well-written your book may be, one book will probably not make your name. Good results are generally speaking obtained by well-written and edited, appropriately priced, frequent publication in the crime/thriller and romance genres.
The E-book market is moving so fast that this is only an interim report, and we may expect to see many changes in the coming months and years.