The good news for writers is that Amazon Kindle and similar platforms allow them to get their books directly to readers. No longer does a writer have to search frantically for an agent and wait to get the nod from one of a handful of major publishing houses.
The bad news is that many self-published novels are not edited, proofread, or scrutinized in any critical way before being offered to the general population. And believe me, some of the novels that show up on Kindle can be described in one word: horrible.
Many others, however, fall into a gray area. They're not really that bad. The characters are solid. The plot has possibilities. The writing is okay. They just contain a few too many rookie mistakes. Most of these mistakes become obvious in the first few pages. Readers who encounter them usually move on to something else. A few of the cranky ones may leave bad reviews.
If you've published a novel that isn't doing as well as you'd hoped, give it another look to make sure it doesn't contain any of the following mistakes.