Avoid writing on over-published topics…
…Unless you really have something different to say, or you can deliver a familiar message in a unique way or format.
A surprisingly large number of people attempt to market books on topics that have already been well covered by others. Ask yourself: Do I have something to say on this topic that has not been said by other authors?
It’s important to consider, because even if you are publishing a book similar to many others, the answer to this question can become your book’s unique selling point. What makes your book different? How will it stand out from the crowd? What makes your book the best book to read on this topic?