It used to be that you could recognize a self-published book simply by the cover. Most were poorly designed and just looked amateur.
That has changed. More authors are aware that covers are an extremely important part of their marketing, and they are taking care to create an engaging presentation with their images, their fonts, and the overall cover design.
One important factor that’s being considered is author and series branding. Having enough similarity between related covers that readers recognize related publications is a great way to help fans find followup books.
On the forum, one writer was asking about the cover for her prequel. Does it need to have a matching cover even though the story isn’t a direct part of the larger series? All members can login and see the advice she received about Illustrating Chaos… complete with pictures!