Book and even updates.
Your due diligence does not stop once your book is published.
What is more exciting than updating the metadata on your books? Everything. Metadata is one of the most overlooked pieces in the publishing process. If you are a new author, or if you were a beginning author, your first one or two books probably went something like this.
You finally finished your edits, cover design, proofreads, interior design, and you are finally ready to get your book published on Amazon and possibly Ingram-Spark, or a book aggregate. You pull up your back of book narrative and paste it into the online description. You may use KDP Publisher for your keywords, or you may have manually crawled through Google to make your searchable list of words. Finally, you figure out your price points and bam, you are ready to go.
Except, you are not ready. Some relevant fields should be filled in, or filled in after the initial launch excitement subsides. One of the most important is your contributors. This information goes overlooked, and if you are self-published, these fields can be a significant differentiator. Many readers assume self-published books are slapped together by people who want to get a book up on Amazon and hope to grab some of the self-publishing pot. So, adding in your editor, and any other contributors shows you are a serious author, and your book is of professional quality.
Also, you should review your description and keywords. Once your core readers have bought your book, you need to attract new readers, and the depiction that made sense to your existing circle of readers may have little attraction to new ones. Do not be afraid to update your short and long descriptions. The beauty of books is that they usually do not age out as fast as other products so that when these updates are seen they draw in new customers.
Although everyone mentions this last part, it always deserves to be mentioned again. Update your keywords. I would recommend reviewing them every six months. However, if you initially slapped down your best guess, take the time to research what people are querying on. I used Publisher Rocket (Formally KDP Rocket.) I have found this to be a beneficial tool and have no issues recommending it.
Finally, make sure you update all your platforms. For me, these include Amazon, Ingram-Spark, and Bowker. Not every site offers the same metadata fields in the same format, so do not plan on a simple copy and paste across platforms. Take your time; it is worth your effort.