One of the hardest questions to answer when you are just starting out as an author and you have been struggling with your book for months/years is: “But how do I know when my book is ready?”
The answer is complicated. Firstly, it depends what you mean by ready. If you want something that is absolutely perfect and as good as it could be, then it will probably never be ready. Because I don’t think there is any such thing as ‘perfect’ when it comes to art. There are just different levels of quality, and some of it is in the eye of the beholder, and some of it comes down to the basics… Is it free of grammatical errors? Is it properly laid out? Does the story make sense? Does it engage the audience it is aiming for? Etc, etc.
I thought this checklist by Chris Robley was worth reading. Some important points to remember. I have been using this for my books, at least trying to! http://blog.bookbaby.com/2015/01/how-to-know-when-youre-done-writing-your-novel/
One of the ways I know that my book is finished is when I finally stop thinking about it and trying to add bits to the story. Sometimes you just know…
The editing and beta reading is also crucial. You need more than one set of eyes to look at it to get some perspective.
Good luck with finishing your books!