“The value of unsolicited, genuine feedback is incalculable.”
Book reviews are awesome – so are random comments about your book on Twitter or elsewhere online. There is just no feeling greater coming across a review of your book that someone else wrote without telling you about. Especially if it is a positive review that not only praises you, but lists a few things that you could work on as well. How do people think you could improve? I once had someone review my book, and then e-mail me telling me how much they loved it and then mentioned a typo that I had missed. They didn't broadcast my mistake for the world, but they wanted my book to be the best it could be. It was pretty awesome of them.
Likewise, I have done the same for a few books, and ended up in some great discussions with them based on their books. Unsolicited feedback is always awesome. You may or may not have had the joy of receiving some for your book, and there really is no way to go about getting it, but all reviews are worthwhile. The important lesson is to listen to what your readers are saying.
Go through some of the reviews for your book (positive and negative) do they give you an idea of how you can grow as a writer? If you have time, go through some blog comments or past e-mails as well.
Days to go: 190